diff --git a/tools/gbagfx/convert_png.c b/tools/gbagfx/convert_png.c
index c9c240efbba0..58371229c06d 100644
--- a/tools/gbagfx/convert_png.c
+++ b/tools/gbagfx/convert_png.c
@@ -62,7 +62,7 @@ static unsigned char *ConvertBitDepth(unsigned char *src, int srcBitDepth, int d
 
         for (j = 8 - srcBitDepth; j >= 0; j -= srcBitDepth)
         {
-            unsigned char pixel = (srcByte >> j) % (1 << destBitDepth);
+            unsigned char pixel = ((srcByte >> j) % (1 << srcBitDepth)) % (1 << destBitDepth);
             *dest |= pixel << destBit;
             destBit -= destBitDepth;
             if (destBit < 0)