diff --git a/src/calibre/gui2/dialogs/trim_image.py b/src/calibre/gui2/dialogs/trim_image.py
index 614e94bd3b..bc0216dc0d 100644
--- a/src/calibre/gui2/dialogs/trim_image.py
+++ b/src/calibre/gui2/dialogs/trim_image.py
@@ -185,7 +185,7 @@ class TrimImage(QDialog):
         if rect:
             x, y, w, h = map(int, self.canvas.rect_for_trim())
             text = f'{int(w)}x{int(h)}'
-            text = _('Size: {0}px Aspect ratio: {1:.3g}').format(text, w / h)
+            text = _('Size: {0}px Aspect ratio: {1:.3g}').format(text, (w / h) if h else 0)
         else:
             text = ''
         self.tr_sz.setText(text)