diff --git a/src/v_video.cpp b/src/v_video.cpp
index f1f218f27..a0495bcfc 100644
--- a/src/v_video.cpp
+++ b/src/v_video.cpp
@@ -563,7 +563,7 @@ void V_UpdateModeSize (int width, int height)
 	else if (w >= 1600 && w < 1920) factor = 3; 
 	else  factor = w / 640;
 
-	CleanYfac_1 = CleanXfac_1 = MAX(1, int (CleanXfac * 0.7));
+	CleanYfac_1 = CleanXfac_1 = MAX(1, int (factor * 0.7));
 	CleanWidth_1 = width / CleanXfac_1;
 	CleanHeight_1 = height / CleanYfac_1;