diff --git a/dice_loss.py b/dice_loss.py
index 631638f..71edf6a 100644
--- a/dice_loss.py
+++ b/dice_loss.py
@@ -21,7 +21,7 @@ class DiceCoeff(Function):
 
         if self.needs_input_grad[0]:
             grad_input = grad_output * 2 * (target * self.union - self.inter) \
-                         / self.union * self.union
+                         / (self.union * self.union)
         if self.needs_input_grad[1]:
             grad_target = None