Compound Interest Calculator

Estimate how your money could grow over time with compound interest. This free compound interest calculator shows future balance, total contributions, total interest earned, and inflation-adjusted value.

Results

Future Balance
$0
Total Contributions
$0
Interest Earned
$0
Inflation-Adjusted Value
$0
Average Annual Growth
$0
Average Monthly Balance
$0

Enter your values and click Calculate to estimate compound growth over time.

How this compound interest calculator works

This compound interest calculator estimates how a starting amount can grow over time when interest is earned on both the original principal and previously earned interest.

It also supports recurring monthly contributions, so you can see the effect of adding money regularly. The results show future balance, total contributions, total interest earned, and an inflation-adjusted value in today’s dollars.

What to enter

  • Your starting amount or principal
  • Your monthly contribution amount
  • Your annual interest rate
  • Your savings or investment period in years
  • Your chosen compounding frequency
  • An inflation rate for real-value comparison

What the results mean

  • Future Balance: projected ending value after compounding
  • Total Contributions: the money you personally added
  • Interest Earned: growth created by compounding
  • Inflation-Adjusted Value: future balance in today’s dollars
  • Average Annual Growth: average yearly increase from interest

Compound interest formula

The standard compound interest formula for a lump sum is:

A = P × (1 + r / n)nt

Where:

When monthly contributions are included, the future value of those recurring deposits is added to the result separately.

Tips for using a compound interest calculator

Start as early as possible

Time is one of the biggest factors in compound growth. Even small balances can grow substantially when given enough time.

Contribute regularly

Consistent monthly contributions can greatly increase the final balance and take full advantage of compounding.

Compare different rates

A slightly higher interest rate can lead to much larger ending values over long periods because the growth compounds on itself.

Look at real purchasing power

Inflation can reduce the value of future money, so comparing the inflation-adjusted result can give a more realistic picture.

Frequently asked questions

What is compound interest?

Compound interest is interest earned on both your original principal and on interest that has already been added to the balance.

How is compound interest different from simple interest?

Simple interest only applies to the original principal, while compound interest grows faster because interest earns interest over time.

Does compounding frequency matter?

Yes. More frequent compounding generally produces a slightly higher ending balance because interest is added more often.

Can I use this for savings or investments?

Yes. This calculator works well for savings accounts, general investing estimates, long-term goals, and other compound growth scenarios.

Related finance calculators