diff --git a/src/Magnum/Test/PrimitiveQueryGLTest.cpp b/src/Magnum/Test/PrimitiveQueryGLTest.cpp
index 4a7074643..ae2881894 100644
--- a/src/Magnum/Test/PrimitiveQueryGLTest.cpp
+++ b/src/Magnum/Test/PrimitiveQueryGLTest.cpp
@@ -280,7 +280,7 @@ void PrimitiveQueryGLTest::transformFeedbackPrimitivesWritten() {
     } shader;
 
     Buffer output;
-    output.setData({nullptr, 18*sizeof(Vector2)}, BufferUsage::StaticDraw);
+    output.setData({nullptr, 9*sizeof(Vector2)}, BufferUsage::StaticDraw);
 
     Mesh mesh;
     mesh.setPrimitive(MeshPrimitive::Triangles)