diff --git a/src/dawn/tests/end2end/CopyExternalTextureForBrowserTests.cpp b/src/dawn/tests/end2end/CopyExternalTextureForBrowserTests.cpp
index 66024c324b..07ccb93dc6 100644
--- a/src/dawn/tests/end2end/CopyExternalTextureForBrowserTests.cpp
+++ b/src/dawn/tests/end2end/CopyExternalTextureForBrowserTests.cpp
@@ -77,7 +77,8 @@ class CopyExternalTextureForBrowserTests : public Parent {
         wgpu::TextureDataLayout externalTexturePlane0DataLayout = {};
         externalTexturePlane0DataLayout.bytesPerRow = 4;
 
-        this->queue.WriteTexture(&plane0, yPlaneData.data(), yPlaneData.size() * sizeof(float),
+        this->queue.WriteTexture(&plane0, yPlaneData.data(),
+                                 yPlaneData.size() * sizeof(yPlaneData[0]),
                                  &externalTexturePlane0DataLayout, &externalTexturePlane0Desc.size);
 
         // uv plane
@@ -99,7 +100,8 @@ class CopyExternalTextureForBrowserTests : public Parent {
         wgpu::TextureDataLayout externalTexturePlane1DataLayout = {};
         externalTexturePlane1DataLayout.bytesPerRow = 4;
 
-        this->queue.WriteTexture(&plane1, uvPlaneData.data(), uvPlaneData.size() * sizeof(float),
+        this->queue.WriteTexture(&plane1, uvPlaneData.data(),
+                                 uvPlaneData.size() * sizeof(uvPlaneData[0]),
                                  &externalTexturePlane1DataLayout, &externalTexturePlane1Desc.size);
 
         // Create an ExternalTextureDescriptor from the texture views