APR Calculator
Convert APY into an equivalent nominal annual rate; this is not a fee-inclusive loan APR.
This tool runs entirely in your browser. Your files are never uploaded to a server.
6.002%
Equivalent nominal annual rate
What this calculator does
Converts an effective annual rate or APY into the equivalent nominal annual interest rate for a selected number of equal compounding periods. Despite the established APR URL, the output is a compounding-only nominal rate, not a regulated consumer-credit APR.
How to use it
Enter the effective annual percentage and an integer compounding frequency from 1 to 366, such as 12 for monthly or 365 for daily. Compare the result only with a rate using the same compounding convention; use the lender's official disclosure when comparing credit products.
Worked example
An effective annual rate of 6.167781% with 12 equal compounding periods converts to a nominal annual rate of 6.000%. Re-entering that 6% nominal rate in the related APY calculator returns approximately 6.167781%, and automated tests verify the round trip.
Formula and precision
For effective decimal rate e and n periods, the nominal decimal rate is n × [(1 + e)^(1/n) − 1]. The implementation uses logarithm and exponential functions that preserve accuracy near zero, retains full floating-point precision internally, and rounds only the displayed percentage to three decimals.
APY and nominal-rate assumptions
The equation assumes one constant periodic rate, equal compounding intervals, reinvestment of interest, no deposits or withdrawals, and a one-year comparison. It does not model tiered or stepped rates, changing balances, early withdrawal, bonuses, fees, day-count conventions, or account-specific rounding.
Why this is not a loan APR
In United States consumer credit, the Consumer Financial Protection Bureau describes APR as a broader cost-of-credit measure that can include interest, points, origination charges, broker fees, and other charges. A compliant closed-end credit APR also depends on the amount and timing of value and payments; this two-input converter cannot calculate it.
Regional terminology and limits
APR, APY, effective annual rate, EAR, nominal rate, TIN, TAE and TAEG are not interchangeable in every country. Legal definitions, included costs, day-count rules and disclosure calculations vary by product and jurisdiction, so do not relabel this mathematical output as an official advertised or contractual rate.
Sources, warning and privacy
The APY concept and annualization rules were checked against CFPB Regulation DD, while the APR distinction was checked against CFPB Regulation Z and consumer guidance; reviewed September 2026. This educational converter is not financial, credit, legal or tax advice. It runs locally in the browser and Quiklio does not upload entered rates. Verify any decision with official disclosures and a qualified professional.
Frequently Asked Questions
- Does this calculate a lender's fee-inclusive APR?
- No. It converts an effective annual rate into a mathematically equivalent nominal rate and has no loan amount, fees, cash-flow dates, or jurisdictional rules needed for an official credit APR.
- Is this the inverse of the APY calculator?
- Yes, when both tools use the same constant rate and number of equal compounding periods. Their results can differ from a bank disclosure that uses actual days, rounding, balance tiers, or other rules.
- What formula is used?
- For APY as a decimal e, it uses nominal rate = n × [(1 + e)^(1/n) − 1], where n is an integer number of equal compounding periods per year.