Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Effective APR
6.449%
Above the quoted rate
0.199%
Monthly payment
$1,847.15
Total of payments
$664,975
Total cost of borrowing
$371,175
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter loan amount ($).
- 2Enter quoted rate (%).
- 3Enter term (years).
- 4Enter fees and points ($).
- 5Read your effective apr on the right — it updates as you type.
- 6Hit Share to keep the scenario or send it to someone.
About this calculator
The interest rate is not the cost of a loan — APR is. Points, origination, and processing fees fold into the effective rate, which is why two loans quoting the same rate can cost very different amounts.
Worked example
Using the values the calculator loads with:
Inputs
- Loan amount: 300000 $
- Quoted rate: 6.25 %
- Term: 30 years
- Fees and points: 6200 $
Results
- Effective APR: 6.449%
- Above the quoted rate: 0.199%
- Monthly payment: $1,847.15
- Total of payments: $664,974.58
- Total cost of borrowing: $371,174.58
What each field means
Inputs
- Loan amount ($)
- The loan amount used in the calculation, measured in $. Starts at 300000 $ so you have a working example on load.
- Quoted rate (%)
- The quoted rate used in the calculation, measured in %. Starts at 6.25 % so you have a working example on load.
- Term (years)
- The term used in the calculation, measured in years. Starts at 30 years so you have a working example on load.
- Fees and points ($)
- The fees and points used in the calculation, measured in $. Starts at 6200 $ so you have a working example on load.
Results
- Effective APR
- Returned as a percentage and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Above the quoted rate
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Monthly payment
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total of payments
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total cost of borrowing
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the apr calculator work?
The interest rate is not the cost of a loan — APR is. Points, origination, and processing fees fold into the effective rate, which is why two loans quoting the same rate can cost very different amounts. The underlying maths is: APR is the rate that equates the financed amount net of fees to the scheduled payment stream.
What do I need to enter?
4 values: loan amount, quoted rate, term, and fees and points. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the effective apr result mean?
It is returned as a percentage and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
Who is this tool for?
It's built for anyone comparing money scenarios before committing — budgeting a payment, sanity-checking a quote, or seeing what a change in rate or term actually costs.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). APR Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/apr
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/apr" target="_blank" rel="noopener">APR Calculator — RevenueLab</a> (2026).</p>
Source: [APR Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/apr) (2026).