Compound interest calculator
How much could my money grow?
Try these numbers
Fictional example · edit any value. Results update automatically.
What is compound interest?
Compound interest means returns can themselves generate further returns. Over time, this can make growth non-linear, but investments can also lose value. Your contributions, your assumed rate and your time horizon each play a different role.
1. Start with a contribution
That is money you put in, not market profit.
2. Apply your assumed rate
This tool compounds monthly using an annual nominal rate divided by 12.
3. Repeat for each month
Monthly deposits arrive at the end of each month. The next month starts from the new balance.
Try a fair comparison
Change the annual rate to 3%, then 7%, then -3%. That helps you see how sensitive long-term projections are to their assumptions. None is guaranteed.
What the projection does NOT include
Inflation, taxes, brokerage fees, currency changes, unpredictable returns and investment losses beyond the modeled constant rate. Historic asset prices do not include your deposits and may omit dividends or corporate-action adjustments.