diff --git a/server/controllers/__tests__/aws.controller.test.js b/server/controllers/__tests__/aws.controller.test.js
new file mode 100644
index 0000000000..a3e062be6f
--- /dev/null
+++ b/server/controllers/__tests__/aws.controller.test.js
@@ -0,0 +1,75 @@
+/**
+ * @jest-environment node
+ */
+import Project from '../../models/project';
+import { listObjectsInS3ForUser } from '../aws.controller';
+
+const mockSend = jest.fn();
+
+jest.mock('../../models/project');
+jest.mock('@aws-sdk/client-s3', () => {
+  const actual = jest.requireActual('@aws-sdk/client-s3');
+  return {
+    ...actual,
+    S3Client: jest.fn().mockImplementation(() => ({
+      send: (...args) => mockSend(...args)
+    }))
+  };
+});
+
+describe('listObjectsInS3ForUser()', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('excludes unreferenced (orphaned) S3 objects from totalSize', async () => {
+    mockSend.mockResolvedValue({
+      Contents: [
+        { Key: 'user1/referenced.png', Size: 100 },
+        { Key: 'user1/orphan.png', Size: 999 }
+      ]
+    });
+    Project.getProjectsForUserId = jest.fn().mockResolvedValue([
+      {
+        id: 'project-1',
+        name: 'sketch one',
+        files: [
+          {
+            name: 'referenced.png',
+            url: 'https://s3.example.com/user1/referenced.png'
+          }
+        ]
+      }
+    ]);
+
+    const result = await listObjectsInS3ForUser('user1');
+
+    expect(result.totalSize).toBe(100);
+    expect(result.assets).toHaveLength(1);
+    expect(result.assets[0].key).toBe('user1/referenced.png');
+  });
+
+  it('counts every object when they are all referenced', async () => {
+    mockSend.mockResolvedValue({
+      Contents: [
+        { Key: 'user1/a.png', Size: 100 },
+        { Key: 'user1/b.png', Size: 50 }
+      ]
+    });
+    Project.getProjectsForUserId = jest.fn().mockResolvedValue([
+      {
+        id: 'project-1',
+        name: 'sketch one',
+        files: [
+          { name: 'a.png', url: 'https://s3.example.com/user1/a.png' },
+          { name: 'b.png', url: 'https://s3.example.com/user1/b.png' }
+        ]
+      }
+    ]);
+
+    const result = await listObjectsInS3ForUser('user1');
+
+    expect(result.totalSize).toBe(150);
+    expect(result.assets).toHaveLength(2);
+  });
+});
diff --git a/server/controllers/aws.controller.js b/server/controllers/aws.controller.js
index b6e03db13c..7bdd8ca281 100644
--- a/server/controllers/aws.controller.js
+++ b/server/controllers/aws.controller.js
@@ -105,7 +105,6 @@ export async function listObjectsInS3ForUser(userId) {
         size: asset.size,
         url: `${process.env.S3_BUCKET_URL_BASE}${asset.key}`
       };
-      totalSize += asset.size;
 
       const wasMatched = projects.some((project) =>
         project.files.some((file) => {
@@ -121,8 +120,11 @@ export async function listObjectsInS3ForUser(userId) {
         })
       );
 
+      // Only count referenced assets toward the limit; unreferenced S3
+      // leftovers aren't shown or deletable in "My Assets".
       if (wasMatched) {
         projectAssets.push(foundAsset);
+        totalSize += asset.size;
       }
     });