# APY Calculator

Calculate APY from any nominal interest rate and compounding frequency. Compare daily, monthly, and annual compounding effects. Free APY calculator.

## What this calculates

Convert a nominal interest rate into the true Annual Percentage Yield based on how often interest compounds. Enter the stated rate and compounding frequency to see your real return, plus the dollar impact on a deposit.

## Inputs

- **Nominal Interest Rate** (%) — min 0, max 100 — The stated annual interest rate before compounding.
- **Compounding Frequency** — options: Annually (1x/year), Semi-Annually (2x/year), Quarterly (4x/year), Monthly (12x/year), Daily (365x/year) — How often interest is compounded per year.
- **Deposit Amount (Optional)** ($) — min 0 — Optional: enter a deposit to see actual dollar earnings.

## Outputs

- **Annual Percentage Yield (APY)** — formatted as percentage — The effective annual return accounting for compounding.
- **APY vs. Nominal Rate Difference** — formatted as percentage — How much more you earn from compounding vs. simple interest.
- **Interest Earned in 1 Year** — formatted as currency — Dollar amount of interest earned on your deposit in one year.
- **Balance After 1 Year** — formatted as currency — Your deposit plus interest after one year.

## Details

Annual Percentage Yield (APY) tells you exactly how much you earn on a deposit after accounting for compound interest. The formula is APY = (1 + r/n)^n - 1, where r is the nominal rate and n is the number of compounding periods per year.

The difference matters more than you might think. A 5.00% nominal rate compounded daily yields an APY of 5.127%, while the same rate compounded annually stays at exactly 5.00%. On a $10,000 deposit, that is the difference between earning $512.67 and $500.00 -- an extra $12.67 from more frequent compounding.

When comparing savings accounts or CDs, always compare APY, not the nominal rate. Banks are required to disclose APY under the Truth in Savings Act. A savings account advertising 4.90% compounded daily (APY 5.02%) actually pays more than one offering 5.00% compounded annually (APY 5.00%). The APY is the apples-to-apples comparison number.

## Frequently Asked Questions

**Q: What is the difference between APY and APR?**

A: APY (Annual Percentage Yield) includes the effect of compounding and shows what you actually earn on deposits. APR (Annual Percentage Rate) is the simple annual rate without compounding and is used for loans. A 5% APR compounded monthly has an APY of 5.116%. For savings, look at APY. For loans, look at APR.

**Q: Does compounding frequency really matter?**

A: Yes, but the impact depends on the interest rate. At 5%, the difference between annual and daily compounding is about 0.13% APY -- $12.67 extra per year on $10,000. At higher rates like 10%, the gap widens to about 0.52% or $51.56 on $10,000. For most savings accounts, the difference between monthly and daily compounding is minimal.

**Q: What is continuous compounding?**

A: Continuous compounding is the theoretical limit of compounding frequency -- interest compounds every instant. The formula is APY = e^r - 1, where e is Euler's number (2.71828). For a 5% rate, continuous compounding gives an APY of 5.127%, virtually identical to daily compounding (5.127%). In practice, daily compounding is the most frequent used by banks.

**Q: How do banks calculate APY on savings accounts?**

A: Most banks compound interest daily and credit it monthly. They calculate daily interest as (annual rate / 365) times your balance, accumulate it through the month, then add it to your balance. The APY they advertise already accounts for this daily compounding, so the number you see is what you actually earn over a year.

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Source: https://vastcalc.com/calculators/finance/apy
Category: Finance
Last updated: 2026-04-08