diff --git a/packages/core/src/client.ts b/packages/core/src/client.ts
index 6a269a969c8d..e0294ef26c59 100644
--- a/packages/core/src/client.ts
+++ b/packages/core/src/client.ts
@@ -1521,12 +1521,8 @@ function estimateMetricSizeInBytes(metric: Metric): number {
     weight += metric.name.length * 2;
   }
 
-  // Add weight for the value
-  if (typeof metric.value === 'string') {
-    weight += metric.value.length * 2;
-  } else {
-    weight += 8; // number
-  }
+  // Add weight for number
+  weight += 8;
 
   return weight + estimateAttributesSizeInBytes(metric.attributes);
 }
diff --git a/packages/core/src/metrics/internal.ts b/packages/core/src/metrics/internal.ts
index 676814f4d4e6..f8e40b5fc0b4 100644
--- a/packages/core/src/metrics/internal.ts
+++ b/packages/core/src/metrics/internal.ts
@@ -201,7 +201,7 @@ export function _INTERNAL_captureMetric(beforeMetric: Metric, options?: Internal
 
   const serializedMetric: SerializedMetric = {
     timestamp: timestampInSeconds(),
-    trace_id: traceId,
+    trace_id: traceId ?? '',
     span_id: spanId,
     name: processedMetric.name,
     type: processedMetric.type,
diff --git a/packages/core/src/metrics/public-api.ts b/packages/core/src/metrics/public-api.ts
index e508fcb9e6d0..7dcfe74dfdb0 100644
--- a/packages/core/src/metrics/public-api.ts
+++ b/packages/core/src/metrics/public-api.ts
@@ -30,7 +30,7 @@ export interface MetricOptions {
  * @param value - The value of the metric.
  * @param options - Options for capturing the metric.
  */
-function captureMetric(type: MetricType, name: string, value: number | string, options?: MetricOptions): void {
+function captureMetric(type: MetricType, name: string, value: number, options?: MetricOptions): void {
   _INTERNAL_captureMetric(
     { type, name, value, unit: options?.unit, attributes: options?.attributes },
     { scope: options?.scope },
diff --git a/packages/core/src/types-hoist/metric.ts b/packages/core/src/types-hoist/metric.ts
index 9201243c4a38..6ac63da6032b 100644
--- a/packages/core/src/types-hoist/metric.ts
+++ b/packages/core/src/types-hoist/metric.ts
@@ -9,7 +9,7 @@ export interface Metric {
   /**
    * The value of the metric.
    */
-  value: number | string;
+  value: number;
 
   /**
    * The type of metric.
@@ -42,7 +42,7 @@ export interface SerializedMetric {
   /**
    * The trace ID for this metric.
    */
-  trace_id?: string;
+  trace_id: string;
 
   /**
    * The span ID for this metric.
@@ -67,7 +67,7 @@ export interface SerializedMetric {
   /**
    * The value of the metric.
    */
-  value: number | string;
+  value: number;
 
   /**
    * Arbitrary structured data that stores information about the metric.
diff --git a/packages/core/test/lib/client.test.ts b/packages/core/test/lib/client.test.ts
index ae324aa40f9f..d50d6da911b8 100644
--- a/packages/core/test/lib/client.test.ts
+++ b/packages/core/test/lib/client.test.ts
@@ -2763,7 +2763,10 @@ describe('Client', () => {
 
       // Create large metrics that will exceed the 800KB threshold
       const largeValue = 'x'.repeat(400_000); // 400KB string
-      _INTERNAL_captureMetric({ name: 'large_metric', value: largeValue, type: 'counter', attributes: {} }, { scope });
+      _INTERNAL_captureMetric(
+        { name: 'large_metric', value: 1, type: 'counter', attributes: { large_value: largeValue } },
+        { scope },
+      );
 
       expect(sendEnvelopeSpy).toHaveBeenCalledTimes(1);
     });