diff --git a/direct/src/interval/ActorInterval.py b/direct/src/interval/ActorInterval.py
index 44cb829f52..b17037ba50 100644
--- a/direct/src/interval/ActorInterval.py
+++ b/direct/src/interval/ActorInterval.py
@@ -87,7 +87,7 @@ class ActorInterval(Interval.Interval):
         self.implicitDuration = 0
         if duration == None:
             self.implicitDuration = 1
-            duration = float(self.numFrames - 1) / self.frameRate
+            duration = float(self.numFrames) / self.frameRate
 
         # Initialize superclass
         Interval.Interval.__init__(self, name, duration)