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Compound Interest Calculator

Estimate growth with compound interest. Processing for supported tools happens locally in your browser.

About Compound Interest Calculator

Use this browser-based utility for everyday tasks. Review output before relying on it and retain a copy of important originals.

Read the Compound Interest Calculator guide →

About Compound Interest Calculator

Compound interest estimates show how interest can build on both an initial balance and previously accumulated interest. This calculator provides a mathematical scenario based on the values you enter.

How to use Compound Interest Calculator

  1. Enter the starting principal.
  2. Enter the annual interest rate as a percentage.
  3. Set the number of years.
  4. Choose how many times interest compounds per year.
  5. Calculate the estimated future value and interest earned.

What the result leaves out

The calculator assumes a constant rate and no deposits or withdrawals. Real savings and investments can have changing rates, fees, taxes and losses, and inflation reduces what the money can buy. Use the number to understand how compounding works and to compare examples, not as a promise of what you will earn or as advice to buy anything.

Frequently asked questions

What is the compound interest formula?

A = P x (1 + r/n)^(n x t), where P is the starting amount, r the yearly rate as a decimal, n the number of times interest is added per year and t the number of years. Compound interest is the interest earned on the interest.

What is the difference between simple and compound interest?

Simple interest is earned only on the starting amount. Compound interest is also earned on the interest that was added before, so it grows faster over time.

How do I enter monthly compounding?

Choose 12 as the number of times interest is added per year.

Does the tool include regular deposits?

No. It assumes one starting amount and no deposits or withdrawals.

More Calculators tools

Want more detail, examples and answers to common questions? Read the Compound Interest Calculator guide.

About Compound Interest Calculator

Compound interest estimates show how interest can build on both an initial balance and previously accumulated interest. This calculator provides a mathematical scenario based on the values you enter.

How to use Compound Interest Calculator

  1. Enter the starting principal.
  2. Enter the annual interest rate as a percentage.
  3. Set the number of years.
  4. Choose how many times interest compounds per year.
  5. Calculate the estimated future value and interest earned.

What the result leaves out

The calculator assumes a constant rate and no deposits or withdrawals. Real savings and investments can have changing rates, fees, taxes and losses, and inflation reduces what the money can buy. Use the number to understand how compounding works and to compare examples, not as a promise of what you will earn or as advice to buy anything.

Frequently asked questions

What is the compound interest formula?

A = P x (1 + r/n)^(n x t), where P is the starting amount, r the yearly rate as a decimal, n the number of times interest is added per year and t the number of years. Compound interest is the interest earned on the interest.

What is the difference between simple and compound interest?

Simple interest is earned only on the starting amount. Compound interest is also earned on the interest that was added before, so it grows faster over time.

How do I enter monthly compounding?

Choose 12 as the number of times interest is added per year.

Does the tool include regular deposits?

No. It assumes one starting amount and no deposits or withdrawals.

More Calculators tools

Want more detail, examples and answers to common questions? Read the Compound Interest Calculator guide.