Overview
Enter a starting principal, an optional recurring contribution per period, an annual interest rate, a time period, and a compounding frequency to calculate future value: the lump sum grows with standard compound interest, and the recurring contributions grow as an ordinary annuity (each contribution is assumed to land at the END of its period, so the very last contribution earns no interest before the term ends - the standard convention, and the one used here). The two pieces are added together for the total future value. This differs from the Compound Interest Calculator, which only grows a single starting principal and has no way to model recurring deposits - use this tool when you're modeling contributions on top of (or instead of) a lump sum, such as a savings plan with monthly deposits. Runs entirely client-side, and this is an informational estimate, not financial advice.
Best for: Projecting how much a savings or investment plan will be worth, including regular recurring deposits
How to use this tool
- Enter starting principal. The lump sum you're starting with (can be zero if you're only contributing periodically).
- Enter a periodic contribution. The amount added at the end of each compounding period (can be zero for a lump-sum-only projection).
- Enter rate, time, and frequency. Annual interest rate, time period in years, and how often interest compounds.
- Read the future value. The combined lump-sum growth plus the future value of your contribution series.
Frequently asked questions
The Compound Interest Calculator only grows a single starting principal - it has no fields for recurring deposits. This tool adds that: a contribution entered here is assumed to be added at the end of every compounding period, and its own future value (as an ordinary annuity) is added to the lump sum's future value.
End-of-period ("ordinary annuity") is the more common convention and the one used here. It assumes each contribution is deposited at the close of a period rather than the start, so the final contribution in the series doesn't have time to earn interest before the term ends. Beginning-of-period contributions would produce a slightly higher total.
Yes - set the periodic contribution to zero and it behaves exactly like a standard compound interest projection.