APR Calculator

Convert a nominal annual rate to a periodic and effective annual rate.

  • Runs locally in your browser
  • No upload required

Try it

Periodic rate
1%
Effective annual rate
12.6825030132%
Compounding
monthly
Periods per year
12
Formula
effective = (1 + 12/100/12)^12 − 1 = 0.126825030132

Supported formats

Input
number, select
Output
number, text

Privacy

Runs entirely in your browser. Your input is never uploaded, stored, or sent to a third party.

Processing
In your browser
Privacy level
Browser only

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).
textSelect to copy
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

  1. Divide the nominal annual rate by the number of compounding periods per year to get the periodic rate.
  2. Compound the periodic rate over one year: effective = (1 + nominal/(100·n))^n − 1.
  3. For continuous compounding, use the limit effective = e^(nominal/100) − 1.
  4. Round the result to 12 significant digits.

Usage

  1. Enter the nominal annual rate as a percentage.
  2. Choose the compounding frequency.
  3. 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

jsonSelect to copy
{
  "nominalRatePercent": 12,
  "compounding": "monthly"
}

5% compounded annually

jsonSelect to copy
{
  "nominalRatePercent": 5,
  "compounding": "annually"
}

10% compounded continuously

jsonSelect to copy
{
  "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

  1. Truth in Lending (Regulation Z), 12 CFR Part 1026 — Consumer Financial Protection Bureau (accessed 2026-10-11)
  2. What is an APR? — Consumer Financial Protection Bureau
  3. Annual percentage rate (APR) and effective annual rate — U.S. Securities and Exchange Commission