Annual Interest to Monthly Calculator

Use our Annual Interest to Monthly Calculator to turn an annual interest rate into its monthly rate — or a monthly rate into its annual rate — as a nominal APR or an effective rate (APY), and see what it earns on a balance in the first year.

A nominal APR, the way loans and credit cards usually quote rates, is simply divided by 12: 12% a year is 1% a month. But 1% a month, with interest added each month, earns 12.682503% over a year — its effective annual rate, or APY. An effective rate, the way savings accounts usually quote rates, is spread over the 12 months by compounding instead: 12% APY is 0.948879% a month, which earns $94.89 in the first month on $10,000 and exactly $1,200 over the year.

Choose Annual rate to go the other way: 0.5% a month is 6% as an APR or 6.167781% as an APY. The results always show the monthly rate, the APR and the APY side by side, each worked out from the exact monthly rate, and with a starting balance, the interest month by month for the first year.

The rate stays the same and interest is added monthly; fees and taxes aren’t included, so treat the results as an estimate. To compare two savings accounts quoted as an APR or an APY, use our Savings Interest Rate Comparison Calculator; to see growth over many years with regular deposits, our Compound Interest Calculator with Contributions.