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Car Loan Calculator

Monthly payment, total interest and the real full cost of your car loan — from price, down payment, trade-in, term and APR. Compare terms side by side before you sign. No signup, everything runs in your browser.

By UpnixTools · Calculator last reviewed October 2026

Monthly payment
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How to Calculate a Car Loan: The Formula

First find the loan amount: car price − down payment − trade-in (+ sales tax if financed). Then the monthly payment comes from the standard amortization formula:

M = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1)

Where P is the loan amount, r the monthly rate (APR ÷ 12), and n the number of monthly payments.

Worked example: a $25,000 car with $5,000 down and no trade-in gives P = $20,000. At 8% APR over 60 months: r = 0.08 ÷ 12 = 0.0066667, n = 60. (1.0066667)^60 ≈ 1.4898, so M = 20,000 × 0.0066667 × 1.4898 ÷ 0.4898 ≈ $405.53/month. Enter the same numbers above and the calculator matches it instantly — then tap the term buttons to see how 36 vs 84 months changes the total interest.

Term trade-off: a longer term (72 or 84 months) shrinks the monthly payment but balloons total interest. Tap the terms above to watch the interest row change — that's the real price of a lower payment.

20% down is the classic rule: it keeps you from owing more than the car is worth and cuts both the payment and the interest.

Car Loan Calculator FAQs

How do you calculate a car loan monthly payment?
Monthly payment = loan amount × monthly rate × (1 + monthly rate)^n ÷ ((1 + monthly rate)^n − 1), where n is the number of monthly payments. Loan amount = price − down payment − trade-in (+ tax/fees if financed).
What is the formula to calculate a car loan?
The car loan formula is M = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1), where P is the loan amount (price − down payment − trade-in), r is the monthly rate (APR ÷ 12), and n is the number of payments. Example: $20,000 at 8% APR over 60 months works out to about $405.53/month — the walkthrough above shows every step.
Is a longer car loan term better?
A longer term lowers your monthly payment but you pay much more interest overall. A 72-month loan at 8% costs far more than a 48-month loan for the same car — this calculator shows the difference instantly.
How much down payment should I put on a car?
20% is the common rule of thumb: it keeps the loan balance below the car's value so you don't owe more than the car is worth, and it lowers your monthly payment and total interest.
Does a trade-in reduce my car loan?
Yes — the trade-in value directly reduces the amount you need to borrow, exactly like a down payment. Enter it above to see the effect on your monthly payment.