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Free Compound Interest Calculator Online

Calculate compound interest, future value, interest earned, total contributions, APY, investment growth, and savings projections with this free compound interest calculator.

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📈 Compound Interest Calculator

Live Compound Growth Estimate

Compound Interest Inputs

Left Side

Initial Principal

Annual Interest Rate (%)

Investment Period

Enter period in years.

Compound Frequency

Monthly Contribution

Contribution Timing

Inflation Rate (%)

Tax Rate on Interest (%)

Optional estimate for after-tax value.

Adjust the inputs to calculate compound interest growth.

Compound Interest Results

Right Side

Future Value$0

Interest Earned$0

Total Contributions$0

Total Deposited$0

APY / Effective Rate0%

After-Tax Value$0

Inflation-Adjusted Value$0

Compound Interest Breakdown Pie Chart

Principal$0

Contributions$0

Interest earned$0

Year	Start Balance	Contributions	Interest	End Balance

Compounding:
Interest earns more interest when growth is added back to the balance.

Contribution impact:
Regular deposits can significantly increase future value.

Estimate only:
Actual savings, investments, taxes, and returns can vary.

What Is a Compound Interest Calculator?

A compound interest calculator estimates how money can grow when interest is added back to the balance and earns more interest over time. It can calculate future value, interest earned, total contributions, APY, investment growth, savings projections, after-tax value, and inflation-adjusted value.

This free online compound interest calculator is useful for savings accounts, investments, retirement planning, long-term goals, and comparing how different interest rates, time periods, and compounding frequencies affect growth.

Compound Growth Calculator

Estimate future value from principal, rate, time, and compounding frequency.

Interest Earned Calculator

See how much growth comes from compound interest over time.

APY Calculator

Calculate the effective annual yield based on compounding frequency.

Savings Projection Table

Review year-by-year balances and export the projection as a CSV file.

How Compound Interest Works

Compound interest works by adding earned interest back to the balance. The next interest calculation then uses the larger balance. Over long periods, this can create faster growth than simple interest because the interest itself starts earning interest.

Compound Interest Formula

A = P(1 + r/n)^ntA = final amount, P = principal, r = annual rate, n = compounding periods per year, t = years

The calculator uses monthly projection logic for contributions and uses the selected compounding frequency to show APY. It also estimates after-tax value and inflation-adjusted value.

Compound Interest Examples

$10,000 at 6%
Estimate how a starting balance grows with monthly compounding over 10 years.

Monthly deposits
Compare future value with and without regular monthly contributions.

APY comparison
Compare daily, monthly, quarterly, and annual compounding.

Benefits of Compound Interest

Long-term growth
Compounding can increase savings and investment value over time.

Goal planning
Estimate whether your savings plan can reach a future goal.

Scenario testing
Compare rates, time periods, deposits, and compounding options.

Compound Interest Planning Tips

Start early so compounding has more time to work.
Compare APY rather than only the stated interest rate.
Review inflation-adjusted value for real purchasing power.
Use realistic return assumptions for investments because returns are not guaranteed.