GROWTH • CONTRIBUTIONS • COMPOUNDING

Compound Interest Calculator

Project growth with contributions, different rates and compounding periods.

Final value$0

Total contributed$0

Interest earned$0

Growth on contributed capital0%

Real value (inflation-adjusted)$0

Effective annual rate0%

What this result means

Rate sensitivity

Same contributions and horizon, with the annual rate two points lower or higher.

Capital growth

Compare accumulated contributions with projected value.

Contributed Projected value

Final value composition

How much comes from contributed capital and how much from interest.

Contributed capital$0

Interest earned$0

Interest share of final value0%

Annual projection

Summary of contributions, interest and accumulated value at the end of each year.

Year	Starting balance	Year contributions	Year interest	Ending balance	Real value (inflation-adjusted)

Important: This tool shows hypothetical scenarios. Future rates are not guaranteed and it is not financial advice.

Method, worked example and assumptions

Example: $5,000 initially plus $250 at the end of each month for 10 years at an 8% nominal APR compounded monthly produces a scenario—not a forecast. The calculator schedules contributions and interest-crediting events separately, then shows nominal value, real purchasing power and the effect of optional annual costs.

Formula: for a principal without contributions, FV = PV × (1 + r/n)^nt. Recurring contributions are modeled on their actual schedule instead of being added as a single lump sum.

How to calculate compound interest with contributions

Compound growth occurs when returns are earned on both the original capital and previously accumulated returns. Enter starting capital, recurring contributions, annual return, compounding frequency, time horizon and inflation to compare nominal growth with inflation-adjusted value.

The calculator is a scenario model. Real investments rarely earn a constant return every period, and taxes, fees and changing rates can materially alter the outcome.

Frequently asked questions

What is compound interest?

Compound interest is growth calculated on the starting amount plus previously accumulated interest or returns.

How do recurring contributions affect compounding?

New contributions increase the capital base that can participate in future growth, so contribution amount and timing can be as important as the assumed return.

Why adjust for inflation?

Inflation reduces purchasing power. Showing a real-value estimate helps compare future money with what a similar amount could buy today.

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