APY Calculator
Convert APR to APY, compare compounding options, estimate interest earned, and generate savings growth schedules with deposits and CSV export.
APY, APR & Savings Growth Estimator
Compute APY from APR, convert APY to APR, estimate interest earned with deposits, and export growth schedules.
Compare annual percentage yield with nominal interest
Annual percentage yield expresses the effect of compounding over a year under a stated rate and compounding schedule. For a nominal annual rate r compounded m times per year, APY = (1 + r/m)^m − 1. If a deposit earns a 5% nominal annual rate with monthly compounding, the resulting APY is approximately 5.116%, assuming the balance remains in the account and the rate does not change.
The difference matters when comparing accounts that compound at different intervals. Two advertised nominal rates can generate different realized growth if interest is credited at different frequencies. Fees, minimum balance requirements, withdrawal limits, bonus-rate expiration dates, and promotional eligibility can matter more than a small difference between two quoted yields.
An APY projection assumes the relevant rate is maintained for the period being modeled. Variable savings rates can change, and deposits or withdrawals alter the actual amount earned even when the annualized rate is accurately calculated. Check the financial institution’s disclosures instead of interpreting a computed yield as a promise of future earnings.