Savings & Interest Calculator
See how a starting balance and regular deposits grow with simple or compound interest.
Learn about growth assumptions with the Investor.gov compound interest calculator.
About Savings & Interest Calculator
This fixed-rate projection calculates interest on an initial balance and each scheduled deposit. Simple interest uses principal × annual rate × years without earning interest on interest. Compound interest uses principal × (1 + annual nominal rate / compounds per year) raised to the number of elapsed compounding periods. Fractional periods use that same equivalent growth rate, including between contribution dates. Contributions are added at the beginning or end of each selected period. A year is 12 equal months; daily compounding uses 365 periods per year. Results exclude fees, taxes, inflation, rate changes and market risk. Amounts share your selected display currency; no exchange conversion occurs. Calculations stay in your browser.
Frequently Asked Questions
No. Enter the nominal annual rate. For compound interest, the tool displays the effective annual rate calculated from your compounding frequency. An advertised APY is already an effective rate; using it with annual compounding reproduces that annual growth assumption.
End timing deposits after each full period, including at the final date. Beginning timing deposits at time zero and the start of each following period, excluding the final date. If contributions are nonzero, the duration must contain whole contribution periods.
Banks may use actual days, minimum balances, transaction dates, daily rounding, fees, taxes or variable rates. This is a mathematical estimate with unrounded intermediate values, not a quote or guaranteed return.