Compound Interest Calculator

Compound Interest: The Eighth Wonder of the World

Unlike simple interest, which is only calculated on the principal amount, compound interest is calculated on the principal plus the accumulated interest from previous periods. This creates a snowball effect that can lead to exponential wealth growth over time.

Why Frequency Matters: The more frequently interest is compounded (e.g., daily vs. annually), the faster your money grows. Daily compounding yields slightly more than monthly, and monthly significantly more than annual.

Key Wealth Building Factors

Time (The Multiplier)

The longer you leave your money invested, the more powerful the compounding effect becomes.

Consistent Contributions

Adding small amounts monthly can drastically change the final outcome compared to a one-time lump sum.

Rate of Return

Even a 1% difference in annual return can result in thousands of dollars over a 30-year period.

Frequently Asked Questions

What is the Rule of 72?

The Rule of 72 is a quick way to estimate how many years it will take for your investment to double. Simply divide 72 by your annual rate of return. (e.g., at an 8% return, your money doubles in 9 years).

Is compound interest taxable?

It depends on the account type. In standard brokerage accounts, interest is generally taxable. In tax-advantaged accounts like a 401(k) or Roth IRA in the US, compounding is tax-deferred or tax-free.

Use Compound Interest Calculator in your browser

Calculate the power of compounding for your investments. Visualize future growth with monthly contributions and customizable compounding frequencies. It runs directly in your browser, so you can start straight away without creating an account or installing anything.

Simple to start

Open the workspace above, choose your options, and get the result when you need it.

Made for any screen

The controls are designed to stay usable on phones, tablets, and desktops.