Compound Interest Calculator

Project how a starting balance can grow with a stated annual rate, time horizon, and optional monthly deposits, so you can compare saving and investing scenarios.

Compound growth shows up in savings accounts, bonds, and long-term portfolios: the earlier you start and the longer you stay invested, the more time returns have to build on themselves. This calculator is illustrative, real products have taxes, fees, and variable rates.

Set monthly contribution to zero to model a single deposit with your chosen compounding frequency (monthly, quarterly, annual, or daily). Add a monthly amount to see recurring savings with monthly compounding on both principal and payments.

Future value20,096.61
Total contributed10,000
Interest earned10,096.61

Growth over time

05.0k10k15k20k0246810Years

Frequently Asked Questions

It is interest earned on both your original balance and on interest that has already been added. Over time, growth can accelerate compared to simple interest, which only pays on the principal.
When you add monthly savings, the tool compounds those deposits at the same monthly rate as the starting balance for consistency. The compound frequency dropdown applies to lump-sum growth when your monthly contribution is zero.
You enter a nominal annual rate (APR-style). Compounding frequency affects effective yield: more frequent compounding with the same nominal rate produces a slightly higher end balance.
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