Compound Interest Calculator

Compounding frequency changes the answer more than most people expect. Pick it explicitly.

Frequency is the quiet lever

The same 12% compounded monthly ends higher than 12% compounded yearly, because interest starts earning interest sooner. The gap is small in year one and large in year twenty.

Rule of 72

Divide 72 by the annual rate to estimate the doubling time: at 12%, about six years.

Is this the same as APR?

No. APR is a borrowing cost; this is the growth of a deposit.

Can I add monthly contributions?

This tool covers a lump sum only — use the savings goal calculator for monthly deposits.

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