APY Calculator

What this calculator does

Convert a fixed nominal annual rate into an effective annual yield for equal periodic compounding, using a positive whole number of compounding periods.

Scope, period, and currency

This page runs a local formula from user-entered values. The country/currency selector changes money symbols and formatting only: it does not perform live or historical FX conversion or automatically change contract, tax, accounting, or regulatory rules. Convert all amounts into one currency first and keep periods and metric definitions consistent.

Formula variables

i

Nominal annual rate as a decimal.

n

Positive integer compounding periods per year.

Formula and worked example

Formula: APY = [(1 + i ÷ n)^n − 1] × 100%.

Recalculation: A 5% nominal annual rate compounded monthly (n = 12) gives APY = 5.1162%, displayed as 5.12%.

Model assumptions

• The nominal rate stays fixed for one year.
• Compounding periods are equal and interest remains in the account.
• Tiered, variable, promotional, fee-based, and day-count products are excluded.

Reading the result and model boundary

• APY is higher than the nominal rate when a positive rate compounds more than once per year.
• A bank's regulated disclosure may use actual days and product-specific rules.

This is a fixed-rate compounding conversion, not a regulated disclosure engine for every deposit product.

How to use it

1. Enter the nominal annual rate.
2. Enter a positive whole number of compounding periods per year.
3. Compare the estimate with the institution's official APY disclosure.

Common incorrect uses

• Entering zero or a fractional compounding frequency.
• Treating a variable or tiered product as a fixed-rate account.
• Calling the estimate a compliant bank disclosure.

Suggested verification workflow

1. Confirm rate and compounding frequency.
2. Calculate mathematical APY.
3. Check fees, balance tiers, dates, and official disclosures.

FAQ

Method and review boundary

Results are calculated locally in the browser from the formula shown on this page. The tool does not retrieve live rates, quotes, approvals, or billing data. Last reviewed: July 24, 2026.

Use the result for first-pass estimates, scenario comparison, and question preparation; it is not financial, investment, tax, accounting, or legal advice.

Authoritative sources and notes

• Regulation DD Appendix A APY rules - Consumer Financial Protection Bureau
• Annual percentage yield definition - Consumer Financial Protection Bureau
• Compound interest calculator - U.S. Securities and Exchange Commission

Sources checked July 24, 2026. Rates, product rules, and official guidance can change; verify them again before a formal decision.