diff --git a/README.md b/README.md
index 0ac326d..0d34df2 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # panosplitter
 
-Split your horizontal images into 4x5 images for Instagram carousel posts.
+Split your horizontal images into 4images of variable aspect ratio (4x5, 1x1, 9x16) for Instagram carousel posts.
 
 # License
 The code in this project is licensed under GPLv3. Except for all images which are not free to use.
diff --git a/index.html b/index.html
index e0f543c..86c079f 100644
--- a/index.html
+++ b/index.html
@@ -18,8 +18,17 @@
                 <img src="images/logo.svg" alt="FUTC Bird Logo" width="100" height="100" class="logo">
             </div>
             <h1>FUTC's Instagram Panorama Slicer</h1>
-            <p>Split your panorama images into Instagram-friendly carousel posts (4:5 aspect ratio)</p>
+            <p>Split your panorama images into Instagram-friendly carousel posts (standard is 4:5 aspect ratio, choose yours below)</p>
             <p>Your photos never leave your computer, all processing is done locally</p>
+
+            <div class="aspect-ratio-selector">
+                <label for="aspect-ratio">Choose aspect ratio:</label>
+                <select id="aspect-ratio" name="aspect-ratio">
+                    <option value="4:5" selected>4:5 (Instagram standard portrait)</option>
+                    <option value="1:1">1:1 (Square)</option>
+                    <option value="9:16">9:16 (Stories/Reels)</option>
+                </select>
+            </div>
         </header>
 
         <!-- Loading overlay -->
diff --git a/script.js b/script.js
index 7fe3c8c..85c4848 100644
--- a/script.js
+++ b/script.js
@@ -1,3 +1,9 @@
+function getAspectRatio(aspectRatioSelect) {
+        const value = aspectRatioSelect.value;
+        const [w, h] = value.split(":").map(Number);
+        return w / h; // returns numerical ratio
+    }
+
 document.addEventListener('DOMContentLoaded', () => {
     // DOM Elements
     const uploadArea = document.getElementById('upload-area');
@@ -21,18 +27,18 @@ document.addEventListener('DOMContentLoaded', () => {
     const loadingText = document.getElementById('loading-text');
     const downloadBtnText = document.querySelector('.btn-text');
     const downloadBtnLoader = document.querySelector('.btn-loader');
+
+    // variable aspectRatio
+    let aspectRatio = getAspectRatio(document.getElementById("aspect-ratio"));
     
     // Variables to store image data
     let originalImage = null;
     let slicedImages = [];
     let fullViewImage = null;
     
-    // Standard Instagram 4:5 aspect ratio
-    const aspectRatio = 4/5; // width:height ratio
-    
     // Standard resolution (for standard mode)
     const standardWidth = 1080;
-    const standardHeight = Math.round(standardWidth / aspectRatio); // Should be 1350
+    let standardHeight = Math.round(standardWidth / aspectRatio); // Should be 1350
     
     const minSlices = 2;
     const halfSliceWidth = standardWidth / 2;
@@ -137,6 +143,16 @@ document.addEventListener('DOMContentLoaded', () => {
             updateImageDetails();
         }
     });
+
+    // Aspect ratio change
+    aspectRatioSelect = document.getElementById("aspect-ratio");
+    aspectRatioSelect.addEventListener('change', () => {
+        if (originalImage) {
+            aspectRatio = getAspectRatio(aspectRatioSelect);
+            standardHeight = Math.round(standardWidth / aspectRatio);
+            updateImageDetails();
+        }
+    });
     
     // Handle file upload
     function handleFile(file) {
@@ -405,6 +421,7 @@ document.addEventListener('DOMContentLoaded', () => {
         if (fullViewImage) {
             const fullViewItem = document.createElement('div');
             fullViewItem.className = 'slice-item full-view-item';
+            fullViewItem.style.aspectRatio = `${fullViewImage.width}/${fullViewImage.height}`;
             
             const img = document.createElement('img');
             img.src = fullViewImage.dataURL;
@@ -428,11 +445,12 @@ document.addEventListener('DOMContentLoaded', () => {
         slicedImages.forEach(slice => {
             const sliceItem = document.createElement('div');
             sliceItem.className = 'slice-item';
+            sliceItem.style.aspectRatio = `${slice.width} / ${slice.height}`;
             
             const img = document.createElement('img');
             img.src = slice.dataURL;
             img.alt = `Slice ${slice.number}`;
-            
+                        
             const number = document.createElement('div');
             number.className = 'slice-number';
             number.textContent = slice.number;
diff --git a/styles.css b/styles.css
index a54dfb2..acc3af4 100644
--- a/styles.css
+++ b/styles.css
@@ -676,4 +676,37 @@ footer {
         flex-direction: row;
         justify-content: space-between;
     }
+}
+
+/* Style for aspect ratio selector */
+.aspect-ratio-selector {
+    margin-top: 1.5rem;
+}
+
+.aspect-ratio-selector label {
+    font-weight: 600;
+    margin-right: 0.5rem;
+    color: #333;
+}
+
+.aspect-ratio-selector select {
+    padding: 0.5rem 1rem;
+    font-size: 1rem;
+    border: 2px solid #ccc;
+    border-radius: 8px;
+    background: white;
+    color: #333;
+    cursor: pointer;
+    transition: all 0.2s ease-in-out;
+}
+
+.aspect-ratio-selector select:hover {
+    border-color: #007bff;
+    box-shadow: 0 0 6px rgba(0, 123, 255, 0.3);
+}
+
+.aspect-ratio-selector select:focus {
+    outline: none;
+    border-color: #0056b3;
+    box-shadow: 0 0 6px rgba(0, 86, 179, 0.3);
 }
\ No newline at end of file