diff --git a/anki/deck.py b/anki/deck.py
index 17608fb4d..016d773d4 100644
--- a/anki/deck.py
+++ b/anki/deck.py
@@ -483,7 +483,7 @@ where id != :id and factId = :factId""",
             if (interval < self.hardIntervalMax and
                 interval > 0.166):
                 mid = (self.midIntervalMin + self.midIntervalMax) / 2.0
-                interval *= (mid / interval / factor)
+                interval = mid / factor
             # multiply last interval by factor
             if ease == 2:
                 interval = (interval + delay/4) * 1.2