diff --git a/src/nsterm.m b/src/nsterm.m
index 776635980e1..a41d6be2045 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -1820,8 +1820,8 @@ x_set_window_size (struct frame *f,
 
   if (pixelwise)
     {
-      pixelwidth = width;
-      pixelheight = height;
+      pixelwidth = FRAME_TEXT_TO_PIXEL_WIDTH (f, width);
+      pixelheight = FRAME_TEXT_TO_PIXEL_HEIGHT (f, height);
     }
   else
     {