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Compound Interest Calculator

Project growth with compound interest and recurring contributions.

Initial investment

Monthly contribution

Annual return (%)

Years

Compounds per year

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Enter your numbers

Your result will appear here.

What this compound interest calculator does

Project how an initial balance and recurring contributions may grow when returns compound over time.

How to use the calculator

Enter the starting amount, assumed annual rate, compounding frequency, contribution amount, contribution frequency and time period. The result separates money you contributed from growth attributable to the assumed rate.

How the calculation works

For periodic compounding, the starting balance grows according to the number of compounding periods, while recurring contributions are accumulated at the applicable periodic rate. The calculation assumes a constant rate and regular contributions.

What the result means

Example: $10,000 earning 5% annually with monthly compounding grows to about $16,470 after 10 years before taxes and fees, with no additional contributions.

Important assumptions and limitations

This is a mathematical projection, not a prediction of investment performance. Real returns vary, investments can lose value, taxes and fees can reduce results, and actual compounding may differ from the assumption.

Frequently asked questions

How does compounding frequency affect growth?
More frequent compounding can increase growth when the nominal annual rate is positive. The calculator models the selected compounding frequency while adding the stated contribution monthly.

Are monthly contributions included?
Yes. The monthly contribution is added at the end of each modeled month, while the annual return is converted from the selected nominal compounding frequency.

Does the calculator account for taxes or investment fees?
No. Taxes, fund expenses, trading costs and account-specific fees are not included.

Is the return guaranteed?
No. An annual return is an assumption for a projection, not a promise of future investment performance.