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Compound Interest Calculator

See how a starting balance and recurring contributions can grow over time, then compare inflation-adjusted value and different return scenarios.

Advanced options: inflation, growing contributions & return range
Investment returns are not guaranteed. A constant annual return is a planning assumption, not a forecast. Taxes, fees and market volatility are not modeled.
Estimated Future Balance
$0.00
Total Contributions
$0.00
Estimated Growth
$0.00
Today's-Dollar Value
$0.00
Effective Annual Yield
0.00%
Growth Share
0.0%
Final balance composition
Your contributionsEstimated growth

Growth Over Time

The chart separates money contributed from estimated compound growth. Values use the assumptions entered above.

StartYear 20

Year-by-Year Growth

See how much you contributed and how much of the balance came from modeled growth each year.

YearEnding BalanceTotal ContributedEstimated GrowthToday's-Dollar Value

How to Use the Results

Contribution timing matters

A contribution made at the beginning of a period has more time to earn a return than the same contribution made at the end. The difference is usually modest per deposit but can accumulate over long horizons.

Inflation changes purchasing power

The nominal future balance tells you the modeled dollar amount. The today's-dollar estimate discounts that future amount by your inflation assumption so you can compare purchasing power more meaningfully.

Growing contributions

If you expect your recurring savings amount to rise over time, the annual contribution-growth option increases the contribution once per year. This can be useful for modeling contributions that rise with income or inflation.

Use a range, not one magic return

Long-term returns are uncertain. The return-range output shows lower and higher mathematical scenarios around your chosen assumption rather than implying one precise outcome.

Methodology & Reference

Compound growth model

Interest is applied using the selected compounding frequency. Recurring contributions are applied at their selected frequency and timing. When frequencies differ, the model advances through daily time steps so deposits and compounding events remain separate rather than converting monthly deposits into artificial daily deposits.

Investor.gov reference

The U.S. Securities and Exchange Commission's Investor.gov compound-interest tool similarly models initial investment, monthly contributions, time, estimated rate, rate variance and compounding frequency.

Investor.gov Compound Interest Calculator

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