What rate of return should I assume?

Many long-term U.S. stock index funds have historically averaged 7–10% annually before inflation, but past performance never guarantees future results.

Does this account for taxes?

No. This is a pre-tax growth estimate; actual returns in a taxable account will typically be lower after taxes on interest, dividends, or gains.

Compound Interest Calculator

Project how your savings grow over time with compounding and monthly contributions.

Initial deposit ($)

Monthly contribution ($)

Annual interest rate (%)

Years to grow

Compounding frequency

Future value Enter your numbers above

Assumes a constant rate of return; real markets fluctuate. Not investment advice.

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How compound interest is calculated

This calculator combines two effects: your lump-sum deposit growing at compound interest, and your regular monthly contributions growing as an annuity. Together they show how consistent saving plus compounding can grow a small starting balance into a much larger sum over time.

Why compounding frequency matters

More frequent compounding (daily vs. annually) slightly increases returns because interest starts earning its own interest sooner. The difference is usually small compared to the impact of your contribution amount and time horizon.

Frequently asked questions

What rate of return should I assume?: Many long-term U.S. stock index funds have historically averaged 7–10% annually before inflation, but past performance never guarantees future results.
Does this account for taxes?: No. This is a pre-tax growth estimate; actual returns in a taxable account will typically be lower after taxes on interest, dividends, or gains.