diff --git a/common/waifu2x.cpp b/common/waifu2x.cpp
index 4ab47b0..6325e5d 100644
--- a/common/waifu2x.cpp
+++ b/common/waifu2x.cpp
@@ -835,7 +835,7 @@ double Waifu2x::CalcScaleRatio(const boost::optional<double> scale_ratio, const
 		return image.GetScaleFromWidth(*scale_width);
 
 	if(scale_height)
-		return image.GetScaleFromWidth(*scale_height);
+		return image.GetScaleFromHeight(*scale_height);
 
 	return 1.0;
 }