diff --git a/py/betterTaesdPreview.py b/py/betterTaesdPreview.py
index e09348f..d038500 100644
--- a/py/betterTaesdPreview.py
+++ b/py/betterTaesdPreview.py
@@ -63,7 +63,7 @@ class BetterTAESDPreviewer(_ORIG_PREVIEWER):
             # Very wide images - prioritize vertical layout.
             cols = min(math.ceil(batch_size / 4), max_cols)
         else:
-            cols = min(math.ceil(batch_size / ratio / 2.0), max_cols)
+            cols = min(math.ceil(batch_size / math.ceil(ratio) / 2.0), max_cols)
         rows = math.ceil(batch_size / cols)
         return cols, rows