Interest Rate Converter Free Online
Convert nominal APR (annual percentage rate) to APY (annual percentage yield, the effective rate) and reverse, given a compounding frequency. Continuous compounding supported.
Results
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Interest Rate Converter Features
APR vs APY
APR is the simple annual rate. APY (effective annual rate, EAR) accounts for compounding within the year. APY ≥ APR always.
All Frequencies
Annual, semiannual, quarterly, monthly, biweekly, weekly, daily, and continuous. Continuous uses e^r exponential growth.
Quick Reference
5% APR monthly = 5.116% APY. 5% APR daily = 5.127% APY. 5% APR continuous = 5.127% APY (limit).
Bidirectional
Convert APR→APY or APY→APR. Both directions handle continuous compounding.
$1,000 Example
See the dollar growth on $1,000 for 1 year at the effective rate.
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All math runs in your browser.
Free vs Pro
| Feature | Free | Pro |
|---|---|---|
| Full interest rate calculation | ||
| Live calculation | ||
| Quick presets | ||
| Bulk CSV / Excel calculation | — | |
| REST API access | — | |
| Save & share calculations | — |
Frequently Asked Questions
APR (Annual Percentage Rate) is the nominal rate. APY (Annual Percentage Yield) is what you actually earn or pay after compounding. APY is always ≥ APR; they are equal only for annual compounding or continuous over zero time.
APY = (1 + 0.05/12)^12 − 1 = 0.05116 = 5.116%. So a 5% APR loan compounded monthly costs 5.116% effectively per year.
The mathematical limit as compounding frequency approaches infinity. APY = e^APR − 1. For APR = 5%, APY = e^0.05 − 1 = 5.127%. Almost identical to daily compounding.
US Truth in Lending Act requires the nominal APR for disclosure. Most credit cards compound daily, so the effective rate is slightly higher (~0.13% on a 24% APR card).
For savings, prefer high APY. For loans, prefer low APY. APY is the true cost/benefit. APR can mislead when compounding differs.