Calculators

APY Calculator

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Calculate Annual Percentage Yield (APY) from APR, project savings growth with compound interest, and compare nominal vs effective rates with monthly or yearly breakdowns.

APY Calculator MMA Calculator
$
APR (%)
APY (%) Annual Percentage Yield — effective yearly return after compounding.

Regular deposits (optional)

$

Calculation results

Future investment value

—

Total interest earned

—

Initial balance

—

Nominal rate → APY

— → —

All-time rate of return (RoR)

—

Time needed to double investment

—

Breakdown choice

View Mode

Month Deposits Interest Accrued interest Balance

Note: Additional contributions are applied at the end of each compounding period, following interest calculation. This calculator is for illustrative purposes only and does not constitute financial advice.

Convert between APR and APY, model future value from an initial deposit and optional regular contributions, and review total interest, rate of return, and time to double your money.

How to use this APY calculator

  1. Choose a currency symbol for display.
  2. Enter your initial deposit and either APR or APY — the other field updates automatically based on your compound interval.
  3. Set duration in years and months, and select how often interest compounds.
  4. Optional: add regular deposits at weekly, monthly, quarterly, half-yearly, or yearly frequency.
  5. Click Calculate — future value, interest earned, APR ↔ APY, RoR, doubling time, and breakdown tables appear on the right.

Modeling a money market account with APY as the quoted rate? Use the Money Market Account Calculator. For full contribution controls and charts, see the Compound Interest Calculator.

What is APY?

Annual Percentage Yield (APY) — sometimes called the effective annual rate — is the total return on a savings or investment account over one year, including the effect of compounding. Unlike nominal APR, APY reflects interest earned on both principal and accumulated interest, making it the standard metric for comparing deposit products.

APY from APR

To convert a nominal APR to APY, raise one plus the periodic rate to the power of compounding periods per year, then subtract one:

r = nominal APR (decimal), n = compounding periods per year

Worked example

$100 at 5% APR compounded monthly for 1 year:

  • APY ≈ 5.12%
  • Future value ≈ $105.12
  • Total interest ≈ $5.12
  • Time to double ≈ 13 years, 11 months at this rate

APY vs APR

APR is the advertised nominal rate before compounding frequency is applied. APY is always equal to or higher than APR when interest compounds more than once per year. Two accounts with the same APR but different compounding intervals will have different APYs — more frequent compounding yields a higher effective return.

Examples and use cases

Real-world use cases

  • High-yield savings hunt: A saver converts two banks’ quoted APR figures (daily vs monthly compounding) to APY before opening an account.
  • CD comparison: Someone checks whether a 5.0% APR CD compounded quarterly beats a 5.05% APY product advertised directly.
  • Emergency fund projection: A user models $10,000 at the calculated APY for one year to estimate interest without manual exponent math.

For interest without compounding, use the Simple Interest Calculator. For MMA-specific projections, try the MMA Calculator.

Common questions

Quick answers before you start calculating.

Annual Percentage Yield (APY) is the effective yearly return on a deposit account, including compounding. The APY Calculator converts APR to APY and projects growth from your inputs.