added a CI calculator.

README.md

@@ -57,3 +57,6 @@ Automatically change home wallpaper adding a random quote and stock tickers on i
 
 ## Script 12 - Star Pattern
 Create a star pattern pyramid
+
+## Script 13 - compound interest calculator 
+calculate compound interest 

calculate_CompoundIntrest.py

@@ -0,0 +1,23 @@
+print('How many years will you be saving?')
+years = int(input('Enter years: '))
+
+print('How much money is currently in your account?')
+principal = float(input('Enter current amount in account: '))
+
+print ('How much money do you plan on investin monthly?')
+monthly_invest = float(input('Enter amount: '))
+
+print ('What do you estimate will be the yearly interest of this investment?') 
+interest = float(input ('Enter interest in decimal numbers (10% = 0.1): '))
+print(' ' )
+
+monthly_invest = monthly_invest * 12
+final_amount = 0
+
+for i in range(0, years):
+    if final_amount == 0:
+        final_amount = principal
+
+final_amount = (final_amount + monthly_invest) * (1 + interest)
+
+print("This is how much money you would have in your account after{} years: ".format (years) + str(final_amount))