diff --git a/subsystems/win32/win32k/eng/surface.c b/subsystems/win32/win32k/eng/surface.c
index 46f96d81c3e..815f67063ca 100644
--- a/subsystems/win32/win32k/eng/surface.c
+++ b/subsystems/win32/win32k/eng/surface.c
@@ -200,18 +200,17 @@ SURFACE_bSetBitmapBits(
     cBitsPixel = gajBitsPerFormat[pso->iBitmapFormat];
 
     /* Is a width in bytes given? */
-    if (!ulWidth)
+    if (ulWidth)
     {
-        /* Calculate width from the bitmap width in pixels */
-        ulWidth = DIB_GetDIBWidthBytes(psurf->SurfObj.sizlBitmap.cx, cBitsPixel);
+        /* Align the width (Windows compatibility, drivers expect that) */
+        ulWidth = WIDTH_BYTES_ALIGN32((ulWidth << 3) / cBitsPixel, cBitsPixel);
     }
 	else
 	{
-		/* Align the width (windows compatibility, drivers expect that) */
-    	ulWidth = ((((ulWidth << 3) / cBitsPixel) * cBitsPixel + 31) & ~31) >> 3;
+        /* Calculate width from the bitmap width in pixels */
+        ulWidth = WIDTH_BYTES_ALIGN32(pso->sizlBitmap.cx, cBitsPixel);
 	}
 
-
     /* Calculate the bitmap size in bytes */
     pso->cjBits = ulWidth * pso->sizlBitmap.cy;
 
diff --git a/subsystems/win32/win32k/include/surface.h b/subsystems/win32/win32k/include/surface.h
index e19a1986425..485f3dc72b3 100644
--- a/subsystems/win32/win32k/include/surface.h
+++ b/subsystems/win32/win32k/include/surface.h
@@ -128,3 +128,7 @@ SURFACE_bSetBitmapBits(
 ULONG FASTCALL BitmapFormat (WORD Bits, DWORD Compression);
 extern UCHAR gajBitsPerFormat[];
 #define BitsPerFormat(Format) gajBitsPerFormat[Format]
+
+#define WIDTH_BYTES_ALIGN32(cx, bpp) ((((cx) * (bpp) + 31) & ~31) >> 3)
+#define WIDTH_BYTES_ALIGN16(cx, bpp) ((((cx) * (bpp) + 15) & ~15) >> 3)
+