diff --git a/gcd.py b/gcd.py
index 0f10da082d7..625bf33a2bd 100644
--- a/gcd.py
+++ b/gcd.py
@@ -5,10 +5,10 @@
 a = int(input("Enter number 1 (a): "))
 b = int(input("Enter number 2 (b): "))
 
-i = 1
-while i <= a and i <= b:
-    if a % i == 0 and b % i == 0:
-        gcd = i
-    i = i + 1
+def calc_GCD(x,y):
+    if y==0:
+        return x
+    return calc_GCD(y,x%y)
+gcd=calc_GCD(a,b)
 
 print("\nGCD of {0} and {1} = {2}".format(a, b, gcd))