diff --git a/rattail/util.py b/rattail/util.py
index 3090958c38d9beee80499b2624ef4eea22f6fe04..a22d0606a4b7f713c061cc771b435166388db4ce 100644
--- a/rattail/util.py
+++ b/rattail/util.py
@@ -187,7 +187,7 @@ def pretty_hours(hours=None, seconds=None):
     if hours is None:
         hours = datetime.timedelta(seconds=seconds)
     minutes = (hours.days * 1440) + (hours.seconds / 60)
-    return '{}:{:02d}'.format(minutes // 60, minutes % 60)
+    return "{}:{:02d}".format(int(minutes // 60), int(minutes % 60))
 
 
 def pretty_quantity(value, empty_zero=False):