diff --git a/face_recognition/cli.py b/face_recognition/cli.py
index 8c109325790f94c99c9827a280d0e0bba425de86..24ef46cf6ae44abe8d02a47bb0c020d1d8686f26 100644
--- a/face_recognition/cli.py
+++ b/face_recognition/cli.py
@@ -34,7 +34,7 @@ def test_image(image_to_check, known_names, known_face_encodings):
 
     # Scale down image if it's giant so things run a little faster
     if unknown_image.shape[1] > 1600:
-        scale_factor = 1600 / unknown_image.shape[1]
+        scale_factor = 1600.0 / unknown_image.shape[1]
         with warnings.catch_warnings():
             warnings.simplefilter("ignore")
             unknown_image = scipy.misc.imresize(unknown_image, scale_factor)