diff --git a/content/svg/content/src/nsSVGSVGElement.cpp b/content/svg/content/src/nsSVGSVGElement.cpp
index 1445772eadf..11ab5c14540 100644
--- a/content/svg/content/src/nsSVGSVGElement.cpp
+++ b/content/svg/content/src/nsSVGSVGElement.cpp
@@ -301,7 +301,8 @@ nsSVGSVGElement::GetScreenPixelToMillimeterX(float *aScreenPixelToMillimeterX)
     return NS_OK;
   }
 
-  *aScreenPixelToMillimeterX = 25.4f / context->AppUnitsToDevPixels(context->AppUnitsPerInch());
+  *aScreenPixelToMillimeterX = 25.4f /
+      nsPresContext::AppUnitsToIntCSSPixels(context->AppUnitsPerInch());
   return NS_OK;
 }