diff --git a/models/event.py b/models/event.py
index 1c40d09..0887f02 100644
--- a/models/event.py
+++ b/models/event.py
@@ -31,9 +31,7 @@ class Event(models.Model):
     def _compute_duration(self):
         for event in self:
             if event.duration is True:
-                fmt = '%Y-%m-%d'
                 t1 = fields.Datetime.from_string(event.date_end)
                 t2 = fields.Datetime.from_string(event.date_start)
-                d1 = datetime.strptime(t1, fmt)
-                d2 = datetime.strptime(t2, fmt)
-                daysDiff = str((d2-d1).day)
+                delta = t1 - t2
+                hours = delta.days * 24.0 + round(float(delta.seconds) / 3600.0)