APR Calculator
Convert a nominal annual rate to a periodic and effective annual rate.
- Runs locally in your browser
- No upload required
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Runs entirely in your browser. Your input is never uploaded, stored, or sent to a third party.
A 12% nominal rate compounded monthly has a periodic rate of 1% and an effective annual rate of 12.6825030132%.
How it works
- Read the nominal annual rate and the compounding frequency.
- Divided the nominal rate by the number of compounding periods for the periodic rate.
- Compounded the periodic rate over a year to obtain the effective annual rate (or used the continuous limit e^r − 1).
effective = (1 + 12/100/12)^12 − 1 = 0.126825030132- A regulated APR can include lender fees and points that this conversion does not know about.
- This is an illustration for information only, not financial advice.
Methodology
- Divide the nominal annual rate by the number of compounding periods per year to get the periodic rate.
- Compound the periodic rate over one year: effective = (1 + nominal/(100·n))^n − 1.
- For continuous compounding, use the limit effective = e^(nominal/100) − 1.
- Round the result to 12 significant digits.
Usage
- Enter the nominal annual rate as a percentage.
- Choose the compounding frequency.
- Read the periodic rate and the effective annual rate with the formula used.
Examples
These are examples, not current values: they use fixed inputs, while the interactive tool computes live results in your browser.
12% compounded monthly
{
"nominalRatePercent": 12,
"compounding": "monthly"
}5% compounded annually
{
"nominalRatePercent": 5,
"compounding": "annually"
}10% compounded continuously
{
"nominalRatePercent": 10,
"compounding": "continuous"
}Limitations
APR versus effective annual rate
In everyday usage 'APR' sometimes means the nominal rate and sometimes the regulated annual percentage rate. This page uses 'APR' as a nominal annual rate and reports its effective annual equivalent. That conversion ignores one-off fees and points, so it is not the regulated APR a lender must disclose.
Frequently asked questions
- What is the difference between APR and APY?
- APY (the effective annual rate) accounts for compounding within the year. A nominal rate quoted as an APR may not, depending on the lender's method and fees, so the same nominal rate can have different effective costs.
- Does this calculate the APR on my loan?
- No. It converts a nominal rate to its effective annual rate. A regulated APR can include fees and points the tool cannot see; use the lender's disclosure for the regulated figure.
Sources
- Truth in Lending (Regulation Z), 12 CFR Part 1026 — Consumer Financial Protection Bureau (accessed 2026-10-11)
- What is an APR? — Consumer Financial Protection Bureau
- Annual percentage rate (APR) and effective annual rate — U.S. Securities and Exchange Commission
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