APY calculator help
The APY Calculator converts a nominal annual rate to APY, an APY back to the nominal rate, and compares compounding frequencies, entirely in your browser.
Conversion Directions
Nominal-to-APY applies (1 + r / n) ^ n - 1 for the selected frequency; continuous
compounding uses e ^ r - 1. APY-to-nominal solves the reverse, finding the nominal rate
that produces the entered APY at that frequency, using the natural log for continuous compounding.
Frequency Comparison
The comparison table recalculates the conversion across annual, semiannual, quarterly, monthly, daily, and continuous compounding, showing the basis-point lift each step adds. Most of the lift comes from compounding at all; daily versus monthly is usually a basis point or two.
Dollar Estimates
Optional balance estimates apply the converted APY to a principal over your chosen term. They assume the money stays deposited the whole time and exclude deposits, withdrawals, fees, taxes, bonuses, promotional windows, and rate changes.
Limitations
The calculator does not rank banks, use live savings or CD rates, or connect to accounts. Account disclosures can apply special APY rules to tiered, stepped, or time accounts, so the issuer's disclosure is authoritative for a specific product.
Related Calculators
Project a balance over time with the compound interest calculator, add fee and inflation assumptions with the investment calculator, or see rate mechanics on the borrowing side in the debt payoff calculator.
FAQ
What is the difference between APY and the nominal annual rate?
The nominal annual rate is the stated rate before compounding. APY is the effective yield over one year after compounding, so it is always at least the nominal rate and grows with compounding frequency. The calculator converts in both directions for the frequency you select.
Which compounding frequencies are supported?
Annual, semiannual, quarterly, monthly, daily, and continuous. The comparison table shows the APY each frequency produces from the same nominal rate, with the lift expressed in basis points.
Is APY the same as APR?
No. APY describes deposit earnings with compounding included. APR describes borrowing cost and is typically quoted without compounding, so a card APR applied monthly costs more over a year than the quoted number suggests. Compare APY with APY for savings and APR with APR for debt.