What will my loan payment be?
Three inputs: amount, rate, term. The calculator returns the fixed monthly payment, adds up the interest over the life of the loan, solves the true APR when an origination fee comes out of the proceeds, and lays out the amortization schedule year by year on the page and month by month in JSON. It fits any fixed-rate loan: personal, auto, or anything else that amortizes.
Loading the calculator.
How the payment is computed
The payment comes from the standard amortization formula: divide the annual rate by twelve, and solve for the one fixed amount that retires the balance exactly at the end of the term. Every month, interest is the monthly rate times the remaining balance and the rest of the payment reduces the balance, so the interest share starts high and falls every month. At 0% the formula collapses to the amount divided by the months.
An origination fee, if you enter one, is modeled the way lenders actually charge it: taken out of the proceeds before you receive them. You repay the full amount but get less cash, which makes the true cost of the money higher than the note rate. The calculator solves that figure, the APR, from the cash flows by asking what rate makes the payments worth exactly the cash you received. It is the same definition behind the APR on a Truth in Lending disclosure.
Extra principal, if you enter it, is paid on top of the regular payment every month. It does not lower the payment; it shortens the loan and cuts the interest, and the result reports the months and dollars saved against the same loan without it.
The default rate is a published statistic, not a guess: the Federal Reserve's G.19 average for a 24-month personal loan at commercial banks. The amount and term are examples to be replaced. Every figure on this page and in the JSON twin comes from one function, so the two never drift.
What a $20,000 loan costs
At the published default rate, $20,000 over 60 months costs $443 a month. You pay $6,609 of interest, 33% of the amount borrowed, and $26,609 in all. The same money over 36 months costs $663 a month but only $3,866 of interest.
The rate depends on what secures the loan. A new car at the G.19 60-month average of 7.14% makes a $35,000 loan cost $695 a month and $6,721 of interest, roughly half the interest share of the unsecured rate, because the lender can repossess the collateral. Home-secured loans run lower still, and credit cards far higher.
Here is the payment across common amounts at the default rate, over five years and over three. Change any input above and the page recomputes as you type.
| Amount | 60 months | Interest | 36 months | Interest |
|---|---|---|---|---|
| $5,000 | $111/mo | $1,652 | $166/mo | $967 |
| $10,000 | $222/mo | $3,304 | $331/mo | $1,933 |
| $20,000 | $443/mo | $6,609 | $663/mo | $3,866 |
| $35,000 | $776/mo | $11,565 | $1,160/mo | $6,766 |
| $50,000 | $1,109/mo | $16,521 | $1,657/mo | $9,665 |
The payment scales exactly with the amount, so the table is really about the term columns: the five-year loan roughly halves the payment of the three-year loan and roughly doubles its interest. That trade, not the amount, is the decision the calculator exists to price.
What moves the payment most
The calculator ranks its own drivers above, in dollars per step, for the inputs you entered. The steps are the sizes people actually negotiate in: a point of rate, a thousand dollars of amount, a year of term, fifty dollars of extra principal.
The rate is where shopping pays. It is set by your credit score, the collateral, and the lender, and the spread between offers for the same borrower is routinely several points. A point on the rate at the defaults changes the total interest by more than any fee a lender will show you in large type.
The term is the lever you control completely. Lenders quote the longer term because the payment looks better; the interest column above is the price of that look. Picking the shortest term whose payment you can actually carry is usually worth more than a point of rate.
Extra principal converts a long term into a short one without giving up the lower required payment. It is the escape hatch when you took the 84-month payment for safety but can usually pay more.
What the calculator does not know
Your rate. The default is a national average for a 24-month personal loan at commercial banks; actual offers depend on your credit score, income, the collateral, and the lender, and finance-company and online-lender rates run a wide range around any average. Enter the quote in front of you.
The model is a fixed-rate, fully amortizing loan. Variable rates, interest-only periods, balloon payments, and precomputed-interest contracts are not modeled. Credit cards do not amortize on a fixed schedule at all; the credit card payoff calculator handles that arithmetic. Taxes, insurance, and late fees are outside the loan and outside this page.
The APR here covers one fee taken from the proceeds. A lender's disclosed APR may fold in other finance charges, and a fee financed on top of the amount rather than deducted from it changes the arithmetic. The disclosure is the binding figure; this page is for understanding it.
For agents and scripts
This calculator is built to be used without a browser. Every input is a query parameter on this page, and the same parameters on the JSON twin return the complete answer as a document.
GET /tools/loan-payment.json?amount=25000&rate=7.14&term=60
The response carries inputs after parsing and clamping, result with the payment, the true APR after fees, the totals, the yearly rows and the complete monthly amortization schedule, plus sensitivity tables by rate, term, and extra principal, drivers ranked by effect with a plain sentence each, assumptions that say for every field whether you supplied it and which source the default came from, sources with URLs and as-of dates, warnings, a disclaimer, and in tool the canonicalUrl and jsonUrl that carry only your non-default parameters. The canonical URL is the answer's permanent address; use it when you cite the number.
Parameters, all optional, in any order:
amount($), default $20,000.rate(%), default 11.86%, from Federal Reserve, G.19 Consumer Credit (June 2026 data).term(months), default 60 months.fee(%), default 0%.extra($ per month), default $0 per month.
Values accept plain numbers and loose human formats such as 100k, $100,000, or 6.5%. Unknown parameters are ignored, values outside a field's range are clamped and reported in warnings, and the endpoint never fails on bad input. Responses are cacheable for a day; the defaults change when their sources publish, and tool.version changes when the method does.
Common questions
What is the monthly payment on a $20,000 loan?
At the published default rate of 11.86% over 60 months, a $20,000 loan costs $443 a month. Over the five years you pay $6,609 of interest, $26,609 in all. That default rate is the Federal Reserve's commercial-bank average for a 24-month personal loan; enter the rate you are quoted and the page recomputes as you type.
How is a loan payment calculated?
By the standard amortization formula: the monthly rate is the annual rate divided by twelve, and the payment is the one fixed amount that retires the balance exactly at the end of the term. Each month's interest is the monthly rate times the remaining balance; the rest of the payment reduces the balance. Early payments are mostly interest because the balance is large, later ones mostly principal. The schedule under the result shows that shift year by year, and the JSON twin carries it month by month.
What does the loan term change?
The split between the payment and the total. At the defaults, $20,000 over 36 months costs $663 a month and $3,866 of interest; over 60 months, $443 and $6,609; over 84 months, $352 and $9,531. A longer term buys a lower payment with more months of interest. The term control under the number shows the payment at each length for your inputs.
What is the difference between the interest rate and the APR?
The interest rate prices the balance; the APR prices the deal, fees included. An origination fee comes out of the money you receive, so you repay $20,000 after getting less than that in cash. At the defaults with a 5% fee, you receive $19,000 and the true APR is 14.14% against the 11.86% note rate. The calculator solves that figure from the actual cash flows when you enter a fee.
Does paying extra each month help?
Yes, and the effect compounds. $100 of extra principal a month at the defaults pays the loan off 14 months sooner and saves $1,626 of interest, because every later month charges interest on a smaller balance. The extra field is under "more assumptions"; most loans covered here have no prepayment penalty, but check the note before counting on it.
Can an agent or a script use this calculator?
Yes. Every input is a query parameter, and the same parameters on /tools/loan-payment.json return the full answer as JSON: inputs, the payment, the APR, totals, the complete month-by-month amortization schedule, drivers, sensitivity tables by rate, term, and extra principal, assumptions with sources, and warnings. No browser, no API key.
Sources
- Federal Reserve, G.19 Consumer Credit (June 2026 data), as of 2026-08-07. Commercial bank interest rates, May 2026: 24-month personal loans 11.86%; 60-month new car loans 7.14%; credit card accounts assessed interest 22.15%.
Default values on this page: rate 11.86% (Federal Reserve, G.19 Consumer Credit (June 2026 data)). The amount and term defaults are examples, and the origination fee and extra principal default to zero.
Want the number for your actual finances?
Carlo is a personal finance agent. It knows your accounts, debts, and goals, so instead of a payment on an example loan it can tell you what this loan does to your savings rate, your payoff order, and the other things you are working toward. Text it the question.
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Written by Tejas Shah, Co-founder, Engineering. Building Carlo — the financial model that begins with the decision you're actually weighing. Previously engineering leadership across fintech and consumer startups.
This models a fixed-rate, fully amortizing loan with a published default for the rate. It is not a loan offer, a rate quote, or financial advice. The lender's disclosure, with its APR and finance charge, is the figure that counts.