diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 6e7fcd59e..02010285e 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -1,4 +1,4 @@
 # These owners will be the default owners for everything in
 # the repo. They will be requested for review when someone
 # opens a pull request.
-*   @SkalskiP @onuralpszr
+*   @SkalskiP @soumik12345
diff --git a/docs/changelog.md b/docs/changelog.md
index 73efcf0b1..4ebec5002 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -1,5 +1,17 @@
 # Changelog
 
+### 0.26.1 <small>Jul 22, 2025</small>
+
+- Fixed [1894](https://github.com/roboflow/supervision/pull/1894): Error in [`sv.MeanAveragePrecision`](https://supervision.roboflow.com/0.26.1/metrics/mean_average_precision/#supervision.metrics.mean_average_precision.MeanAveragePrecision) where the area used for size-specific evaluation (small / medium / large) was always zero unless explicitly provided in `sv.Detections.data`.
+
+- Fixed [1895](https://github.com/roboflow/supervision/pull/1895): `ID=0` bug in [`sv.MeanAveragePrecision`](https://supervision.roboflow.com/0.26.1/metrics/mean_average_precision/#supervision.metrics.mean_average_precision.MeanAveragePrecision) where objects were getting `0.0` mAP despite perfect IoU matches due to a bug in annotation ID assignment.
+
+- Fixed [1898](https://github.com/roboflow/supervision/pull/1898): Issue where [`sv.MeanAveragePrecision`](https://supervision.roboflow.com/0.26.1/metrics/mean_average_precision/#supervision.metrics.mean_average_precision.MeanAveragePrecision) could return negative values when certain object size categories have no data.
+
+- Fixed [1901](https://github.com/roboflow/supervision/pull/1901): `match_metric` support for [`sv.Detections.with_nms`](https://supervision.roboflow.com/0.26.1/metrics/mean_average_precision/#supervision.detection.core.Detections.with_nms).
+
+- Fixed [1906](https://github.com/roboflow/supervision/pull/1906): `border_thickness` parameter usage for [`sv.PercentageBarAnnotator`](https://supervision.roboflow.com/0.26.1/metrics/mean_average_precision/#supervision.annotators.core.PercentageBarAnnotator).
+
 ### 0.26.0 <small>Jul 16, 2025</small>
 
 !!! failure "Removed"
@@ -153,7 +165,7 @@
 
 - Changed [#1786](https://github.com/roboflow/supervision/pull/1786): Significantly improved the speed of HSV color mapping in [`sv.HeatMapAnnotator`](https://supervision.roboflow.com/0.26.0/detection/annotators/#supervision.annotators.core.HeatMapAnnotator), achieving approximately 28x faster performance on 1920x1080 frames.
 
-- Fix [#1834](https://github.com/roboflow/supervision/pull/1834): Supervision’s [`sv.MeanAveragePrecision`](https://supervision.roboflow.com/0.26.0/metrics/mean_average_precision/#supervision.metrics.mean_average_precision.MeanAveragePrecision) is now fully aligned with [pycocotools](https://github.com/ppwwyyxx/cocoapi), the official COCO evaluation tool, ensuring accurate and standardized metrics. This update enabled us to launch a new version of the [Computer Vision Model Leaderboard](https://leaderboard.roboflow.com/).
+- Fixed [#1834](https://github.com/roboflow/supervision/pull/1834): Supervision’s [`sv.MeanAveragePrecision`](https://supervision.roboflow.com/0.26.0/metrics/mean_average_precision/#supervision.metrics.mean_average_precision.MeanAveragePrecision) is now fully aligned with [pycocotools](https://github.com/ppwwyyxx/cocoapi), the official COCO evaluation tool, ensuring accurate and standardized metrics. This update enabled us to launch a new version of the [Computer Vision Model Leaderboard](https://leaderboard.roboflow.com/).
 
     ```python
     import supervision as sv
@@ -173,7 +185,7 @@
     # Average Precision (AP) @[ IoU=0.50:0.95 | area= large | maxDets=100 ] = 0.629
     ```
 
-- Fix [#1767](https://github.com/roboflow/supervision/pull/1767): Fixed losing `sv.Detections.data` when detections filtering.
+- Fixed [#1767](https://github.com/roboflow/supervision/pull/1767): Fixed losing `sv.Detections.data` when detections filtering.
 
 ### 0.25.0 <small>Nov 12, 2024</small>
 
@@ -557,9 +569,9 @@ detections = sv.Detections.from_sam(sam_result=sam_result)
 
 - Changed [#1434](https://github.com/roboflow/supervision/pull/1434): [`InferenceSlicer`](https://supervision.roboflow.com/0.23.0/detection/tools/inference_slicer/) now features an `overlap_wh` parameter, making it easier to compute slice sizes when handling overlapping slices.
 
-- Fix [#1448](https://github.com/roboflow/supervision/pull/1448): Various annotator type issues have been resolved, supporting expanded error handling.
+- Fixed [#1448](https://github.com/roboflow/supervision/pull/1448): Various annotator type issues have been resolved, supporting expanded error handling.
 
-- Fix [#1348](https://github.com/roboflow/supervision/pull/1348): Introduced a new method for [seeking to a specific video frame](https://supervision.roboflow.com/0.23.0/utils/video/#supervision.utils.video.get_video_frames_generator), addressing cases where traditional seek methods were failing. It can be enabled with `iterative_seek=True`.
+- Fixed [#1348](https://github.com/roboflow/supervision/pull/1348): Introduced a new method for [seeking to a specific video frame](https://supervision.roboflow.com/0.23.0/utils/video/#supervision.utils.video.get_video_frames_generator), addressing cases where traditional seek methods were failing. It can be enabled with `iterative_seek=True`.
 
 ```python
 import supervision as sv
@@ -572,7 +584,7 @@ for frame in sv.get_video_frames_generator(
     ...
 ```
 
-- Fix [#1424](https://github.com/roboflow/supervision/pull/1424): `plot_image` function now clearly indicates that the size is in inches.
+- Fixed [#1424](https://github.com/roboflow/supervision/pull/1424): `plot_image` function now clearly indicates that the size is in inches.
 
 !!! failure "Removed"
 
@@ -1285,7 +1297,7 @@ array([
 
 ### 0.11.1 <small>June 29, 2023</small>
 
-- Fix [#165](https://github.com/roboflow/supervision/pull/165): [`as_folder_structure`](/0.11.1/dataset/core/#supervision.dataset.core.ClassificationDataset.as_folder_structure) fails to save [`sv.ClassificationDataset`](/0.11.1/dataset/core/#classificationdataset) when it is result of inference.
+- Fixed [#165](https://github.com/roboflow/supervision/pull/165): [`as_folder_structure`](/0.11.1/dataset/core/#supervision.dataset.core.ClassificationDataset.as_folder_structure) fails to save [`sv.ClassificationDataset`](/0.11.1/dataset/core/#classificationdataset) when it is result of inference.
 
 ### 0.11.0 <small>June 28, 2023</small>
 
@@ -1331,7 +1343,7 @@ array([
 
 - Added [#162](https://github.com/roboflow/supervision/pull/162): additional `start` and `end` arguments to [`sv.get_video_frames_generator`](/0.11.0/utils/video/#get_video_frames_generator) allowing to generate frames only for a selected part of the video.
 
-- Fix [#157](https://github.com/roboflow/supervision/pull/157): incorrect loading of YOLO dataset class names from `data.yaml`.
+- Fixed [#157](https://github.com/roboflow/supervision/pull/157): incorrect loading of YOLO dataset class names from `data.yaml`.
 
 ### 0.10.0 <small>June 14, 2023</small>
 
diff --git a/pyproject.toml b/pyproject.toml
index 1b830697a..cae78492a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -2,7 +2,7 @@
 name = "supervision"
 description = "A set of easy-to-use utils that will come in handy in any Computer Vision project"
 license = { text = "MIT" }
-version = "0.26.0"
+version = "0.26.1"
 readme = "README.md"
 requires-python = ">=3.9"
 authors = [
diff --git a/supervision/annotators/core.py b/supervision/annotators/core.py
index 6c142db19..0b7d4b763 100644
--- a/supervision/annotators/core.py
+++ b/supervision/annotators/core.py
@@ -2239,8 +2239,11 @@ def __init__(
         self.position: Position = position
         self.color_lookup: ColorLookup = color_lookup
 
-        if border_thickness is None:
-            self.border_thickness = int(0.15 * self.height)
+        self.border_thickness = (
+            border_thickness
+            if border_thickness is not None
+            else int(0.15 * self.height)
+        )
 
     @ensure_cv2_image_for_annotation
     def annotate(
diff --git a/supervision/detection/core.py b/supervision/detection/core.py
index efaa366a3..ea466b895 100644
--- a/supervision/detection/core.py
+++ b/supervision/detection/core.py
@@ -1939,8 +1939,8 @@ def with_nms(
             class_agnostic (bool): Whether to perform class-agnostic
                 non-maximum suppression. If True, the class_id of each detection
                 will be ignored. Defaults to False.
-            overlap_metric (OverlapMetric): Metric used for measuring overlap between
-                detections in slices.
+            overlap_metric (OverlapMetric): Metric used to compute the degree of
+                overlap between pairs of masks or boxes (e.g., IoU, IoS).
 
         Returns:
             Detections: A new Detections object containing the subset of detections
@@ -2003,8 +2003,8 @@ def with_nmm(
             class_agnostic (bool): Whether to perform class-agnostic
                 non-maximum merging. If True, the class_id of each detection
                 will be ignored. Defaults to False.
-            overlap_metric (OverlapMetric): Metric used for measuring overlap between
-                detections in slices.
+            overlap_metric (OverlapMetric): Metric used to compute the degree of
+                overlap between pairs of masks or boxes (e.g., IoU, IoS).
 
         Returns:
             Detections: A new Detections object containing the subset of detections
diff --git a/supervision/detection/tools/inference_slicer.py b/supervision/detection/tools/inference_slicer.py
index ff4a44b28..aaecccb3d 100644
--- a/supervision/detection/tools/inference_slicer.py
+++ b/supervision/detection/tools/inference_slicer.py
@@ -9,7 +9,7 @@
 from supervision.config import ORIENTED_BOX_COORDINATES
 from supervision.detection.core import Detections
 from supervision.detection.utils.boxes import move_boxes, move_oriented_boxes
-from supervision.detection.utils.iou_and_nms import OverlapFilter
+from supervision.detection.utils.iou_and_nms import OverlapFilter, OverlapMetric
 from supervision.detection.utils.masks import move_masks
 from supervision.utils.image import crop_image
 from supervision.utils.internal import (
@@ -75,8 +75,8 @@ class InferenceSlicer:
             filtering or merging overlapping detections in slices.
         iou_threshold (float): Intersection over Union (IoU) threshold
             used when filtering by overlap.
-        match_metric (str): Metric used for matching detections in slices.
-            "IOU" or "IOS". Defaults "IOU".
+        overlap_metric (Union[OverlapMetric, str]): Metric used for matching detections
+            in slices.
         callback (Callable): A function that performs inference on a given image
             slice and returns detections.
         thread_workers (int): Number of threads for parallel execution.
@@ -96,7 +96,7 @@ def __init__(
         overlap_wh: tuple[int, int] | None = None,
         overlap_filter: OverlapFilter | str = OverlapFilter.NON_MAX_SUPPRESSION,
         iou_threshold: float = 0.5,
-        match_metric: str = "IOU",
+        overlap_metric: OverlapMetric | str = OverlapMetric.IOU,
         thread_workers: int = 1,
     ):
         if overlap_ratio_wh is not None:
@@ -112,7 +112,7 @@ def __init__(
 
         self.slice_wh = slice_wh
         self.iou_threshold = iou_threshold
-        self.match_metric = match_metric
+        self.overlap_metric = OverlapMetric.from_value(overlap_metric)
         self.overlap_filter = OverlapFilter.from_value(overlap_filter)
         self.callback = callback
         self.thread_workers = thread_workers
@@ -173,11 +173,11 @@ def callback(image_slice: np.ndarray) -> sv.Detections:
             return merged
         elif self.overlap_filter == OverlapFilter.NON_MAX_SUPPRESSION:
             return merged.with_nms(
-                threshold=self.iou_threshold, match_metric=self.match_metric
+                threshold=self.iou_threshold, overlap_metric=self.overlap_metric
             )
         elif self.overlap_filter == OverlapFilter.NON_MAX_MERGE:
             return merged.with_nmm(
-                threshold=self.iou_threshold, match_metric=self.match_metric
+                threshold=self.iou_threshold, overlap_metric=self.overlap_metric
             )
         else:
             warnings.warn(
diff --git a/supervision/detection/utils/iou_and_nms.py b/supervision/detection/utils/iou_and_nms.py
index 56bdff71b..1a6f80bc5 100644
--- a/supervision/detection/utils/iou_and_nms.py
+++ b/supervision/detection/utils/iou_and_nms.py
@@ -164,7 +164,8 @@ def box_iou_batch(
             `shape = (N, 4)` where `N` is number of true objects.
         boxes_detection (np.ndarray): 2D `np.ndarray` representing detection boxes.
             `shape = (M, 4)` where `M` is number of detected objects.
-        overlap_metric (OverlapMetric): Metric used for matching detections in slices.
+        overlap_metric (OverlapMetric): Metric used to compute the degree of overlap
+            between pairs of boxes (e.g., IoU, IoS).
 
     Returns:
         np.ndarray: Pairwise IoU of boxes from `boxes_true` and `boxes_detection`.
@@ -381,7 +382,8 @@ def _mask_iou_batch_split(
     Args:
         masks_true (np.ndarray): 3D `np.ndarray` representing ground-truth masks.
         masks_detection (np.ndarray): 3D `np.ndarray` representing detection masks.
-        overlap_metric (OverlapMetric): Metric used for matching detections in slices.
+        overlap_metric (OverlapMetric): Metric used to compute the degree of overlap
+            between pairs of masks (e.g., IoU, IoS).
 
     Returns:
         np.ndarray: Pairwise IoU of masks from `masks_true` and `masks_detection`.
@@ -433,7 +435,8 @@ def mask_iou_batch(
     Args:
         masks_true (np.ndarray): 3D `np.ndarray` representing ground-truth masks.
         masks_detection (np.ndarray): 3D `np.ndarray` representing detection masks.
-        overlap_metric (OverlapMetric): Metric used for matching detections in slices.
+        overlap_metric (OverlapMetric): Metric used to compute the degree of overlap
+            between pairs of masks (e.g., IoU, IoS).
         memory_limit (int): memory limit in MB, default is 1024 * 5 MB (5GB).
 
     Returns:
@@ -492,7 +495,8 @@ def mask_non_max_suppression(
             dimensions of each mask.
         iou_threshold (float): The intersection-over-union threshold
             to use for non-maximum suppression.
-        overlap_metric (OverlapMetric): Metric used for matching detections in slices.
+        overlap_metric (OverlapMetric): Metric used to compute the degree of overlap
+            between pairs of masks (e.g., IoU, IoS).
         mask_dimension (int): The dimension to which the masks should be
             resized before computing IOU values. Defaults to 640.
 
@@ -543,7 +547,8 @@ def box_non_max_suppression(
             or `(x_min, y_min, x_max, y_max, score, class)`.
         iou_threshold (float): The intersection-over-union threshold
             to use for non-maximum suppression.
-        overlap_metric (OverlapMetric): Metric used for matching detections in slices.
+        overlap_metric (OverlapMetric): Metric used to compute the degree of overlap
+            between pairs of boxes (e.g., IoU, IoS).
 
     Returns:
         np.ndarray: A boolean array indicating which predictions to keep after n
@@ -603,7 +608,8 @@ def _group_overlapping_masks(
             the predictions.
         iou_threshold (float): The intersection-over-union threshold
             to use for non-maximum suppression. Defaults to 0.5.
-        overlap_metric (OverlapMetric): Metric used for matching detections in slices.
+        overlap_metric (OverlapMetric): Metric used to compute the degree of overlap
+            between pairs of masks (e.g., IoU, IoS).
 
     Returns:
         list[list[int]]: Groups of prediction indices be merged.
@@ -664,7 +670,8 @@ def mask_non_max_merge(
             to use for non-maximum suppression.
         mask_dimension (int): The dimension to which the masks should be
             resized before computing IOU values. Defaults to 640.
-        overlap_metric (OverlapMetric): Metric used for matching detections in slices.
+        overlap_metric (OverlapMetric): Metric used to compute the degree of overlap
+            between pairs of masks (e.g., IoU, IoS).
 
     Returns:
         np.ndarray: A boolean array indicating which predictions to keep after
@@ -717,7 +724,8 @@ def _group_overlapping_boxes(
             and the confidence scores.
         iou_threshold (float): The intersection-over-union threshold
             to use for non-maximum suppression. Defaults to 0.5.
-        overlap_metric (OverlapMetric): Metric used for matching detections in slices.
+        overlap_metric (OverlapMetric): Metric used to compute the degree of overlap
+            between pairs of boxes (e.g., IoU, IoS).
 
     Returns:
         list[list[int]]: Groups of prediction indices be merged.
@@ -765,7 +773,8 @@ def box_non_max_merge(
             detections of different classes to be merged.
         iou_threshold (float): The intersection-over-union threshold
             to use for non-maximum suppression. Defaults to 0.5.
-        overlap_metric (OverlapMetric): Metric used for matching detections in slices.
+        overlap_metric (OverlapMetric): Metric used to compute the degree of overlap
+            between pairs of boxes (e.g., IoU, IoS).
 
     Returns:
         list[list[int]]: Groups of prediction indices be merged.
diff --git a/supervision/metrics/mean_average_precision.py b/supervision/metrics/mean_average_precision.py
index 5100f39ac..43a3116ac 100644
--- a/supervision/metrics/mean_average_precision.py
+++ b/supervision/metrics/mean_average_precision.py
@@ -57,7 +57,11 @@ class and IoU threshold. Shape: `(num_target_classes, num_iou_thresholds)`
 
     @property
     def map50_95(self) -> float:
-        return self.mAP_scores.mean()
+        valid_scores = self.mAP_scores[self.mAP_scores > -1]
+        if len(valid_scores) > 0:
+            return valid_scores.mean()
+        else:
+            return -1
 
     @property
     def map50(self) -> float:
@@ -421,6 +425,11 @@ def load_predictions(self, predictions: list[dict]) -> EvaluationDataset:
         if not isinstance(predictions, list):
             raise ValueError("results must be a list")
 
+        # Handle empty predictions
+        if len(predictions) == 0:
+            predictions_dataset.dataset["annotations"] = []
+            return predictions_dataset
+
         ids = [pred["image_id"] for pred in predictions]
 
         # Make sure the image ids from predictions exist in the current dataset
@@ -909,6 +918,35 @@ def _accumulate(self):
                             np.array(score_at_recall)
                         )
 
+        self.results = {
+            "params": self.params,
+            "counts": [
+                num_iou_thresholds,
+                num_recall_thresholds,
+                num_categories,
+                num_area_ranges,
+                num_max_detections,
+            ],
+            "date": datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
+            "precision": precision,
+            "recall": recall,
+            "scores": scores,
+        }
+
+        # Helper function to compute average precision while handling -1 sentinel values
+        def compute_average_precision(precision_slice):
+            """Compute average precision while handling -1 sentinel values."""
+            masked = np.ma.masked_equal(precision_slice, -1)
+            if masked.count() == 0:
+                # All values are -1 (no data)
+                return np.full(num_iou_thresholds, -1), np.full(
+                    (num_categories, num_iou_thresholds), -1
+                )
+            else:
+                mAP_scores = np.ma.filled(masked.mean(axis=(1, 2)), -1)
+                ap_per_class = np.ma.filled(masked.mean(axis=1), -1).transpose(1, 0)
+                return mAP_scores, ap_per_class
+
         # Average precision over all sizes, 100 max detections
         area_range_idx = list(ObjectSize).index(ObjectSize.ALL)
         max_100_dets_idx = self.params.max_dets.index(100)
@@ -917,10 +955,9 @@ def _accumulate(self):
             :, :, :, area_range_idx, max_100_dets_idx
         ]
         # mAP over thresholds (dimension=num_thresholds)
-        mAP_scores_all_sizes = average_precision_all_sizes.mean(axis=(1, 2))
-        # AP per class
-        ap_per_class_all_sizes = average_precision_all_sizes.mean(axis=1).transpose(
-            1, 0
+        # Use masked array to exclude -1 values when computing mean
+        mAP_scores_all_sizes, ap_per_class_all_sizes = compute_average_precision(
+            average_precision_all_sizes
         )
 
         # Average precision for SMALL objects and 100 max detections
@@ -928,24 +965,27 @@ def _accumulate(self):
         average_precision_small = precision[
             :, :, :, small_area_range_idx, max_100_dets_idx
         ]
-        mAP_scores_small = average_precision_small.mean(axis=(1, 2))
-        ap_per_class_small = average_precision_small.mean(axis=1).transpose(1, 0)
+        mAP_scores_small, ap_per_class_small = compute_average_precision(
+            average_precision_small
+        )
 
         # Average precision for MEDIUM objects and 100 max detections
         medium_area_range_idx = list(ObjectSize).index(ObjectSize.MEDIUM)
         average_precision_medium = precision[
             :, :, :, medium_area_range_idx, max_100_dets_idx
         ]
-        mAP_scores_medium = average_precision_medium.mean(axis=(1, 2))
-        ap_per_class_medium = average_precision_medium.mean(axis=1).transpose(1, 0)
+        mAP_scores_medium, ap_per_class_medium = compute_average_precision(
+            average_precision_medium
+        )
 
         # Average precision for LARGE objects and 100 max detections
         large_area_range_idx = list(ObjectSize).index(ObjectSize.LARGE)
         average_precision_large = precision[
             :, :, :, large_area_range_idx, max_100_dets_idx
         ]
-        mAP_scores_large = average_precision_large.mean(axis=(1, 2))
-        ap_per_class_large = average_precision_large.mean(axis=1).transpose(1, 0)
+        mAP_scores_large, ap_per_class_large = compute_average_precision(
+            average_precision_large
+        )
 
         self.results = {
             "params": self.params,
@@ -1221,7 +1261,7 @@ def _prepare_targets(self, targets):
         for image_id, image_targets in enumerate(targets):
             if self._image_indices is not None:
                 image_id = self._image_indices[image_id]
-            for target in image_targets:
+            for target_idx, target in enumerate(image_targets):
                 xyxy = target[0]  # or xyxy = prediction[0]; xyxy[2:4] -= xyxy[0:2]
                 xywh = [xyxy[0], xyxy[1], xyxy[2] - xyxy[0], xyxy[3] - xyxy[1]]
                 # Get "area" and "iscrowd" (default 0) from data
@@ -1231,13 +1271,20 @@ def _prepare_targets(self, targets):
                     category_id = self._class_mapping[target[3].item()]
                 else:
                     category_id = target[3].item()
+
+                # Use area from data if available (e.g., COCO datasets)
+                # Otherwise use Detections.area property
+                area = data.get("area") if data else None
+                if area is None:
+                    area = image_targets.area[target_idx]
+
                 dict_annotation = {
-                    "area": data.get("area", 0),
+                    "area": area,
                     "iscrowd": data.get("iscrowd", 0),
                     "image_id": image_id,
                     "bbox": xywh,
                     "category_id": category_id,
-                    "id": len(annotations),  # incrementally increase the id
+                    "id": len(annotations) + 1,  # Start IDs from 1 (0 means no match)
                 }
                 annotations.append(dict_annotation)
         # Category list
diff --git a/test/metrics/test_mean_average_precision.py b/test/metrics/test_mean_average_precision.py
new file mode 100644
index 000000000..f17cb1cec
--- /dev/null
+++ b/test/metrics/test_mean_average_precision.py
@@ -0,0 +1,328 @@
+"""
+Tests for Mean Average Precision ID=0 bug fix
+"""
+
+import numpy as np
+
+from supervision.detection.core import Detections
+from supervision.metrics.mean_average_precision import MeanAveragePrecision
+
+
+def test_single_perfect_detection():
+    """Test that single perfect detection gets 1.0 mAP (not 0.0 due to ID=0 bug)"""
+    # Perfect detection (identical prediction and target)
+    detection = Detections(
+        xyxy=np.array([[10, 10, 50, 50]], dtype=np.float64),
+        class_id=np.array([0]),
+        confidence=np.array([0.9]),
+    )
+
+    metric = MeanAveragePrecision()
+    metric.update([detection], [detection])
+    result = metric.compute()
+
+    # Should be perfect 1.0 mAP, not 0.0 due to ID=0 bug
+    assert abs(result.map50_95 - 1.0) < 1e-6
+
+
+def test_multiple_perfect_detections():
+    """Test that multiple perfect detections get 1.0 mAP"""
+    # Multiple perfect detections in one image
+    detections = Detections(
+        xyxy=np.array(
+            [[10, 10, 50, 50], [100, 100, 140, 140], [200, 200, 240, 240]],
+            dtype=np.float64,
+        ),
+        class_id=np.array([0, 0, 0]),
+        confidence=np.array([0.9, 0.9, 0.9]),
+    )
+
+    metric = MeanAveragePrecision()
+    metric.update([detections], [detections])
+    result = metric.compute()
+
+    # Should be perfect 1.0 mAP
+    assert abs(result.map50_95 - 1.0) < 1e-6
+
+
+def test_batch_updates_perfect_detections():
+    """Test that batch updates with perfect detections get 1.0 mAP"""
+    # Single perfect detection for multiple batch updates
+    detection = Detections(
+        xyxy=np.array([[10, 10, 50, 50]], dtype=np.float64),
+        class_id=np.array([0]),
+        confidence=np.array([0.9]),
+    )
+
+    metric = MeanAveragePrecision()
+    # Add 3 batch updates
+    metric.update([detection], [detection])
+    metric.update([detection], [detection])
+    metric.update([detection], [detection])
+    result = metric.compute()
+
+    # Should be perfect 1.0 mAP across all batches
+    assert abs(result.map50_95 - 1.0) < 1e-6
+
+
+def test_scenario_1_success_case_imperfect_match():
+    """Scenario 1: Success Case with imperfect match"""
+    # Small object (class 0) - area = 30*30 = 900 < 1024
+    small_perfect = Detections(
+        xyxy=np.array([[10, 10, 40, 40]], dtype=np.float64),
+        class_id=np.array([0]),
+        confidence=np.array([0.95]),
+        data={"area": np.array([900])},
+    )
+
+    # Medium object (class 1) - area = 50*50 = 2500 (between 1024 and 9216)
+    medium_target = Detections(
+        xyxy=np.array([[10, 10, 60, 60]], dtype=np.float64),
+        class_id=np.array([1]),
+        data={"area": np.array([2500])},
+    )
+    medium_pred = Detections(
+        xyxy=np.array([[12, 12, 60, 60]], dtype=np.float64),  # Slightly off
+        class_id=np.array([1]),
+        confidence=np.array([0.9]),
+        data={"area": np.array([2304])},  # 48*48
+    )
+
+    # Large objects (classes 0, 1, 2) - area = 100*100 = 10000 > 9216
+    large_targets = Detections(
+        xyxy=np.array(
+            [[10, 10, 110, 110], [120, 120, 220, 220], [230, 230, 330, 330]],
+            dtype=np.float64,
+        ),
+        class_id=np.array([2, 0, 1]),
+        data={"area": np.array([10000, 10000, 10000])},
+    )
+    large_preds = Detections(
+        xyxy=np.array(
+            [[10, 10, 110, 110], [120, 120, 220, 220], [230, 230, 330, 330]],
+            dtype=np.float64,
+        ),
+        class_id=np.array([2, 0, 1]),
+        confidence=np.array([0.9, 0.9, 0.9]),
+        data={"area": np.array([10000, 10000, 10000])},
+    )
+
+    metric = MeanAveragePrecision()
+    metric.update([small_perfect], [small_perfect])
+    metric.update([medium_pred], [medium_target])
+    metric.update([large_preds], [large_targets])
+    result = metric.compute()
+
+    # Should be close to 0.9 (slightly less than perfect due to medium object)
+    assert 0.85 < result.map50_95 < 0.98  # Adjusted upper bound
+    assert result.medium_objects.map50_95 < 1.0  # Medium should be less than perfect
+
+
+def test_scenario_2_missed_detection():
+    """Scenario 2: GT Present, No Prediction (Missed Detection)"""
+    # Small object - area = 30*30 = 900 < 1024
+    small_detection = Detections(
+        xyxy=np.array([[10, 10, 40, 40]], dtype=np.float64),
+        class_id=np.array([0]),
+        confidence=np.array([0.95]),
+        data={"area": np.array([900])},
+    )
+
+    # Medium object - area = 50*50 = 2500 (between 1024 and 9216) - missed
+    medium_target = Detections(
+        xyxy=np.array([[10, 10, 60, 60]], dtype=np.float64),
+        class_id=np.array([1]),
+        data={"area": np.array([2500])},
+    )
+    no_medium_pred = Detections.empty()
+
+    # Large objects - area = 100*100 = 10000 > 9216
+    large_detections = Detections(
+        xyxy=np.array(
+            [[10, 10, 110, 110], [120, 120, 220, 220], [230, 230, 330, 330]],
+            dtype=np.float64,
+        ),
+        class_id=np.array([2, 0, 1]),
+        confidence=np.array([0.9, 0.9, 0.9]),
+        data={"area": np.array([10000, 10000, 10000])},
+    )
+
+    metric = MeanAveragePrecision()
+    metric.update([small_detection], [small_detection])
+    metric.update([no_medium_pred], [medium_target])
+    metric.update([large_detections], [large_detections])
+    result = metric.compute()
+
+    # Medium objects should have 0.0 mAP (missed detection)
+    assert abs(result.medium_objects.map50_95 - 0.0) < 1e-6
+
+
+def test_scenario_3_false_positive():
+    """Scenario 3: No GT, Prediction Present (False Positive)"""
+    # Small object - area = 30*30 = 900 < 1024
+    small_detection = Detections(
+        xyxy=np.array([[10, 10, 40, 40]], dtype=np.float64),
+        class_id=np.array([0]),
+        confidence=np.array([0.95]),
+        data={"area": np.array([900])},
+    )
+
+    # Medium object - area = 50*50 = 2500 - false positive (no GT)
+    medium_pred = Detections(
+        xyxy=np.array([[12, 12, 62, 62]], dtype=np.float64),
+        class_id=np.array([1]),
+        confidence=np.array([0.9]),
+        data={"area": np.array([2500])},
+    )
+    no_medium_target = Detections.empty()
+
+    # Large objects - area = 100*100 = 10000 > 9216
+    large_detections = Detections(
+        xyxy=np.array(
+            [[10, 10, 110, 110], [120, 120, 220, 220], [230, 230, 330, 330]],
+            dtype=np.float64,
+        ),
+        class_id=np.array([2, 0, 1]),
+        confidence=np.array([0.9, 0.9, 0.9]),
+        data={"area": np.array([10000, 10000, 10000])},
+    )
+
+    metric = MeanAveragePrecision()
+    metric.update([small_detection], [small_detection])
+    metric.update([medium_pred], [no_medium_target])
+    metric.update([large_detections], [large_detections])
+    result = metric.compute()
+
+    # Medium objects should have -1 mAP (false positive, matching pycocotools)
+    assert result.medium_objects.map50_95 == -1
+
+
+def test_scenario_4_no_data():
+    """Scenario 4: No GT, No Prediction (Category has no data)"""
+    # Small object - area = 30*30 = 900 < 1024
+    small_detection = Detections(
+        xyxy=np.array([[10, 10, 40, 40]], dtype=np.float64),
+        class_id=np.array([0]),
+        confidence=np.array([0.95]),
+        data={"area": np.array([900])},
+    )
+
+    # Medium object - no data at all
+    no_medium = Detections.empty()
+
+    # Large objects - area = 100*100 = 10000 > 9216 - only classes 0 and 2 (no class 1)
+    large_targets = Detections(
+        xyxy=np.array(
+            [
+                [10, 10, 110, 110],
+                [120, 120, 220, 220],
+            ],
+            dtype=np.float64,
+        ),
+        class_id=np.array([2, 0]),
+        data={"area": np.array([10000, 10000])},
+    )
+    large_preds = Detections(
+        xyxy=np.array(
+            [
+                [10, 10, 110, 110],
+                [120, 120, 220, 220],
+            ],
+            dtype=np.float64,
+        ),
+        class_id=np.array([2, 0]),
+        confidence=np.array([0.9, 0.9]),
+        data={"area": np.array([10000, 10000])},
+    )
+
+    metric = MeanAveragePrecision()
+    metric.update([small_detection], [small_detection])
+    metric.update([no_medium], [no_medium])
+    metric.update([large_preds], [large_targets])
+    result = metric.compute()
+
+    # Should NOT have negative mAP values for overall
+    assert result.map50_95 >= 0.0
+    # Medium objects should have -1 mAP (no data, matching pycocotools)
+    assert result.medium_objects.map50_95 == -1
+
+
+def test_scenario_5_only_one_class_present():
+    """Scenario 5: Only 1 of 3 Classes Present (Perfect Match)"""
+    # Only class 0 objects with perfect matches
+    detections_class_0 = [
+        Detections(
+            xyxy=np.array([[10, 10, 40, 40]], dtype=np.float64),
+            class_id=np.array([0]),
+            confidence=np.array([0.95]),
+        ),
+        Detections(
+            xyxy=np.array([[20, 20, 230, 130]], dtype=np.float64),
+            class_id=np.array([0]),
+            confidence=np.array([0.9]),
+        ),
+    ]
+
+    metric = MeanAveragePrecision()
+    for det in detections_class_0:
+        metric.update([det], [det])
+
+    result = metric.compute()
+
+    # Should be 1.0 mAP (perfect match for the only class present)
+    assert abs(result.map50_95 - 1.0) < 1e-6
+    assert abs(result.map50 - 1.0) < 1e-6
+    assert abs(result.map75 - 1.0) < 1e-6
+
+
+def test_mixed_classes_with_missing_detections():
+    """Test mixed scenario with some classes having no detections"""
+    # Class 0: Perfect detection
+    class_0_det = Detections(
+        xyxy=np.array([[10, 10, 50, 50]], dtype=np.float64),
+        class_id=np.array([0]),
+        confidence=np.array([0.9]),
+    )
+
+    # Class 1: GT exists but no prediction
+    class_1_target = Detections(
+        xyxy=np.array([[60, 60, 100, 100]], dtype=np.float64),
+        class_id=np.array([1]),
+    )
+    class_1_pred = Detections.empty()
+
+    # Class 2: Prediction exists but no GT (false positive)
+    class_2_pred = Detections(
+        xyxy=np.array([[110, 110, 150, 150]], dtype=np.float64),
+        class_id=np.array([2]),
+        confidence=np.array([0.8]),
+    )
+    class_2_target = Detections.empty()
+
+    metric = MeanAveragePrecision()
+    metric.update([class_0_det], [class_0_det])
+    metric.update([class_1_pred], [class_1_target])
+    metric.update([class_2_pred], [class_2_target])
+    result = metric.compute()
+
+    # Should not have negative mAP
+    assert result.map50_95 >= 0.0
+    # Should be less than 1.0 due to missed detection and false positive
+    assert result.map50_95 < 1.0
+
+
+def test_empty_predictions_and_targets():
+    """Test completely empty predictions and targets"""
+    metric = MeanAveragePrecision()
+    metric.update([Detections.empty()], [Detections.empty()])
+    result = metric.compute()
+
+    # Should return -1 for no data (matching pycocotools behavior)
+    assert result.map50_95 == -1
+    assert result.map50 == -1
+    assert result.map75 == -1
+
+    # All object size categories should also be -1
+    assert result.small_objects.map50_95 == -1
+    assert result.medium_objects.map50_95 == -1
+    assert result.large_objects.map50_95 == -1
diff --git a/test/metrics/test_mean_average_precision_area.py b/test/metrics/test_mean_average_precision_area.py
new file mode 100644
index 000000000..832620961
--- /dev/null
+++ b/test/metrics/test_mean_average_precision_area.py
@@ -0,0 +1,131 @@
+from __future__ import annotations
+
+import numpy as np
+import pytest
+
+from supervision.detection.core import Detections
+from supervision.metrics.mean_average_precision import MeanAveragePrecision
+
+
+class TestMeanAveragePrecisionArea:
+    """Test area calculation in MeanAveragePrecision."""
+
+    @pytest.mark.parametrize(
+        "xyxy, expected_areas, expected_size_maps",
+        [
+            (
+                np.array(
+                    [
+                        [10, 10, 40, 40],  # Small: 900
+                        [100, 100, 200, 150],  # Medium: 5000
+                        [300, 300, 500, 400],  # Large: 20000
+                    ],
+                    dtype=np.float32,
+                ),
+                [900.0, 5000.0, 20000.0],
+                {"small": True, "medium": True, "large": True},
+            ),
+            (
+                np.array([[0, 0, 10, 10]], dtype=np.float32),  # Small: 100
+                [100.0],
+                {"small": True, "medium": False, "large": False},
+            ),
+            (
+                np.array([[0, 0, 50, 50]], dtype=np.float32),  # Medium: 2500
+                [2500.0],
+                {"small": False, "medium": True, "large": False},
+            ),
+            (
+                np.array([[0, 0, 100, 100]], dtype=np.float32),  # Large: 10000
+                [10000.0],
+                {"small": False, "medium": False, "large": True},
+            ),
+        ],
+    )
+    def test_area_calculation_and_size_specific_map(
+        self, xyxy, expected_areas, expected_size_maps
+    ):
+        """Test area calculation and size-specific mAP functionality."""
+        gt = Detections(
+            xyxy=xyxy,
+            class_id=np.arange(len(xyxy)),
+        )
+        pred = Detections(
+            xyxy=gt.xyxy.copy(),
+            class_id=gt.class_id.copy(),
+            confidence=np.full(len(xyxy), 0.9),
+        )
+
+        map_metric = MeanAveragePrecision()
+        map_metric.update([pred], [gt])
+
+        # Test area calculation
+        prepared_targets = map_metric._prepare_targets(map_metric._targets_list)
+        areas = [ann["area"] for ann in prepared_targets["annotations"]]
+        assert np.allclose(areas, expected_areas), (
+            f"Expected {expected_areas}, got {areas}"
+        )
+
+        # Test size-specific mAP
+        result = map_metric.compute()
+
+        if expected_size_maps["small"]:
+            assert result.small_objects.map50 > 0.9, (
+                "Small objects should have high mAP"
+            )
+        else:
+            assert result.small_objects.map50 == -1.0, (
+                "Small objects should have no data"
+            )
+
+        if expected_size_maps["medium"]:
+            assert result.medium_objects.map50 > 0.9, (
+                "Medium objects should have high mAP"
+            )
+        else:
+            assert result.medium_objects.map50 == -1.0, (
+                "Medium objects should have no data"
+            )
+
+        if expected_size_maps["large"]:
+            assert result.large_objects.map50 > 0.9, (
+                "Large objects should have high mAP"
+            )
+        else:
+            assert result.large_objects.map50 == -1.0, (
+                "Large objects should have no data"
+            )
+
+    def test_area_preserved_from_data(self):
+        """Test that area from data field is preserved (COCO case)."""
+        gt = Detections(
+            xyxy=np.array(
+                [[100, 100, 200, 150]], dtype=np.float32
+            ),  # Would calculate to 5000
+            class_id=np.array([0]),
+        )
+        # Override with custom area
+        gt.data = {"area": np.array([3000.0])}
+
+        pred = Detections(
+            xyxy=gt.xyxy.copy(),
+            class_id=gt.class_id.copy(),
+            confidence=np.array([0.9]),
+        )
+        pred.data = {"area": np.array([3000.0])}
+
+        map_metric = MeanAveragePrecision()
+        map_metric.update([pred], [gt])
+
+        prepared_targets = map_metric._prepare_targets(map_metric._targets_list)
+        used_area = prepared_targets["annotations"][0]["area"]
+
+        assert np.allclose(used_area, 3000.0), (
+            f"Should use provided area 3000.0, got {used_area}"
+        )
+
+        # Verify it's different from what would be calculated
+        calculated_area = (200 - 100) * (150 - 100)  # 100 * 50 = 5000
+        assert not np.allclose(used_area, calculated_area), (
+            "Should use provided area, not calculated"
+        )