Python Program To Calculate Simple Interest (

Before getting into the code of calculating Simple Interest in Python, lets understand how simple interest is calculated.

What is Simple Interest?

Simple Interest is the amount of interest charge that you need to pay to the bank when you borrow money from them (a loan). There are three important variables that you would need to understand when writing your python program.

  1. Principal Amount (P): Principal is the amount that you have borrowed from the bank or the base price of the good or service that you have purchased and applied for a loan. Example if you brought a mortgage for $75,0000 USD than this amount is your principal.
  2. Interest Rate (R): Interest rate is the price you need to pay to the bank for the Principal (Loan Amount) you borrowed. This is usually calculate annually. Interest is calculate in percentage. Example for a mortgage loan of $750,000 USD if the internet rate is 10% for a year (annual interest) then you need to pay $75,000 interest every year.
  3. No of days (N): This is the tenor of the loan amount that you and the counter party have agreed upon.

Formula for Simple Interest

Simple Interest = (P [Principal Amount] X N [No of days] X R [Interest Rate]) / 100

Python code for Simple Interest calculation:

# This is a Python program to calculate
# Simple Interest  for the inputted 
# Principal Amount, Rate of Interest,
# and Time frame
# Formula: (P x N x R)/100
# author:
def simple_interest_function(principal_amount,time_period_in_years,rate_of_interest): 

    print("Python Program to calculate Simple Interest") 

    print("Entered Principal Amount:     ", principal_amount) 
    print("Entered Time Period in Years: ", time_period_in_years) 
    print("Entered Rate of Interest:     ",rate_of_interest) 

    #Formula for Simple Interest
    simple_interest =  (principal_amount * time_period_in_years * rate_of_interest)/100

    print("Simple Interest Calculated:   ", simple_interest)

simple_interest_function(750000, 1, 10) 
Python Program to calculate Simple Interest
Entered Principal Amount:      750000
Entered Time Period in Years:  1
Entered Rate of Interest:      10
Simple Interest Calculated:    75000.0
Output - Python Program to calculate Simple Interest


  • Thank you for the detailed example! It was useful for me!
    01 Oct 2020 16:10:18 GMT
  • Further comments disabled!
Try Out Code2care Dev Tools:


Android Java Linux Microsoft Google Python macOS Notepad++ Microsoft Teams CSS PHP SharePoint Html Linux C Programs Bootstrap jQuery Sublime Android Studio Facebook Eclipse WhatsApp News MySQL Json HowTos JavaScript FTP S3


Code2care is an initiative to publish and share varied knowledge in programming and technical areas gathered during day-to-day learnings and development activities.

Students and Software Developers can leverage this portal to find solutions to their various queries without re-inventing the wheel by referring to our easy to understand posts. Technical posts might include Learnings, Tutorials, Trouble-Shooting steps, Video Tutorials, Code Snippets, How Tos, Blogs, Articles, etc.
🎉 We are celebrating the 10th years of Code2care! Thank you for all your support! We hope we made a difference.
We strong support Gender Equality & Diversity.

We stand in solidarity with Ukraine - Make a donation to UNHCR -