Compound Interest Calculator

This calculator shows how much money you will have after a period of time, based on initial amount invested, interest rate, and the number of times compounded.
Amount Invested (P): $

Annual interest rate (r): %

Period of Time (t):

Compound Frequency (n):
(Annual=1, Semi-Annual=2, Quarterly=4, Monthly=12)


Interest and Principal  (A): $

* When entering the percentage value, input the percentage without a decimal  -- i.e. 5% is 5; the calculator considers the decimal
Principal: The money you invest with a bank or investment company.
Interest rate: The amount of money you get paid yearly for every dollar you invest
Time: Length of time money will be in the bank or with the investment company.
Compound Frequency: How often interest is calculated.

Compounded yearly = 1
Compounded semiannually (6 month basis) = 2
Compounded quarterly (4 month basis) = 4
Compounded monthly = 12
Compounded daily = 365

To make navigation on this page easier, select the topic you are interested in learning more about:
- Compound Interest Formula

- Sample Problem

- Video Tutorial for Compounding & Simple Interest

Video Tutorial

The following is a really good explanation of compounding interest and simple interest

Compound Interest Formula

The formula to calculate compound interest (when finding A) is:

A = P(1 + r/n)nt


  • A = Amount of investment after interest has been compounded
  • P = Principal amount (initial investment)
  • r = Annual interest rate
  • n = Number of times the interest is compounded per year
  • t = Number of years (time)