# Calculating Principal And Interest Payments For A Loan Using Python And Numpy

## Overview:

• The Python library numpy has the functions ppmt() and ipmt() to calculate the monthly principal payment and interest payment.
• For a given loan, the sum of the return value of the above two functions is equal to the value returned by the function pmt().

## Example:

 import numpy as np   interestRate        = 0.07 numberOfMonths      = 25*12; principalBorrowed   = 3500000   principal2Pay   = np.ppmt(interestRate/12, 1, numberOfMonths, principalBorrowed); interest2Pay    = np.ipmt(interestRate/12, 1, numberOfMonths, principalBorrowed);   print("Loan amount:%7.2f"%principalBorrowed); print("Loan duration in months:%d"%numberOfMonths); print("Annual Interest Rate in percent:%2.2f"%(interestRate*100));   print("Principal to be paid:%5.2f"%abs(principal2Pay)); print("Interest to be paid:%5.2f"%abs(interest2Pay)); print("Principal+Interest, to be paid:%5.2f"%abs(principal2Pay+interest2Pay));

## Output:

 Loan amount:3500000.00 Loan duration in months:300 Annual Interest Rate in percent:7.00 Principal to be paid:4320.61 Interest to be paid:20416.67 Principal+Interest, to be paid:24737.27