diff --git a/tkintermapview/map_widget.py b/tkintermapview/map_widget.py
index 11975ed..3e6cc78 100644
--- a/tkintermapview/map_widget.py
+++ b/tkintermapview/map_widget.py
@@ -816,9 +816,9 @@ def mouse_zoom(self, event):
         relative_mouse_y = event.y / self.height
 
         if sys.platform == "darwin":
-            new_zoom = self.zoom + event.delta * 0.1
+            new_zoom = self.zoom + int(event.delta * 0.1)
         elif sys.platform.startswith("win"):
-            new_zoom = self.zoom + event.delta * 0.01
+            new_zoom = self.zoom + int(event.delta * 0.01)
         elif event.num == 4:
             new_zoom = self.zoom + 1
         elif event.num == 5: