Auto Loan Payment Calculator

How this is calculated

Two steps. Work out what is actually being borrowed, then run the standard amortization formula over it.

price out the door = cash price + sales tax + title, registration and fees
net trade-in       = trade-in allowance − what you still owe on it
amount financed    = price out the door − cash down − net trade-in

monthly payment    M = P × r ÷ (1 − (1 + r)⁻ⁿ)
                     P = amount financed
                     r = APR ÷ 100 ÷ 12
                     n = the term, in months

total of payments  = M × n
interest           = total of payments − amount financed

still owed at month k
                   = P(1 + r)ᵏ − M × ((1 + r)ᵏ − 1) ÷ r

A net trade-in that comes out negative is not an error. If the payoff on your old car is larger than what the dealer allows for it, the difference is added to the new loan — the minus sign puts it into the principal, where the contract puts it too. At a 0% promotional APR both formulas collapse to plain division, which is handled rather than rejected.

Why there is no “loan amount” field

Because a field labelled that way gets the price of the car typed into it, and the answer comes back low by everything else the lender is financing. This is the most common way an auto-loan estimate is wrong, and it is wrong in the direction that flatters the purchase. The construction used here is not our invention — it is the one the Truth in Lending Act sets out in Regulation Z, 12 CFR § 1026.18(b), which defines the amount financed as “the amount of credit provided to you or on your behalf” and gives the three steps for arriving at it: determining the principal loan amount or the cash price “(subtracting any downpayment)”, then “[a]dding any other amounts that are financed by the creditor and are not part of the finance charge”, then “[s]ubtracting any prepaid finance charge.”

Sales tax, title, registration and dealer fees are that second step. So is an underwater trade-in's unpaid balance. They are financed, and they are not the finance charge — which is why they belong in the principal and why the rows on this page are laid out to match the itemization on your contract.

The figures the same regulation makes the lender name

The output rows use the disclosure's own vocabulary, and each of those terms has a legally-required plain-English description printed beside it on the paperwork you sign. The finance chargeis “the dollar amount the credit will cost you.” The annual percentage rateis “the cost of your credit as a yearly rate.” The total of paymentsis “the amount you will have paid when you have made all scheduled payments.” When you sit down at the desk, the figures on this page and the figures in that box should be recognisably the same figures — if they are not, something has been added that you were not expecting.

One honest difference. This tool amortizes the fees you enter along with the car, which is how a dealer normally treats a documentation fee written into the contract. Where a fee is instead a prepaidfinance charge, the legal disclosure subtracts it from the amount financed and adds it to the finance charge. The monthly payment is identical either way; the split between the two lines is not. So read the interest figure here as interest, not as a reproduction of your contract's finance charge.

What the term actually buys

The two headline figures on this page move in opposite directions when you change the term, and that is the whole finding. Financing $26,030 at 6.9% costs $622.11 a month over 48 months and $391.59 over 84 — but the interest rises from $3,831 to $6,864. The long term buys about $231 a month of relief for roughly $3,000. Whether that is worth it is yours to decide; this page will not pretend the trade does not exist in either direction.

There is a second cost that no interest figure shows. A long loan pays the balance down more slowly than the car loses value, so it leaves you owing more than the car is worth for far longer. That is why the tool asks what month you might sell, and prints the exact balance on that date: it is the number a sale, a trade, or an insurance write-off would have to clear before you see a cent. What it cannot tell you is what the car will be worth on the same date — depreciation is a different question, and no loan calculator knows the answer.

What this does not cover

What the car will be worth. The balance still owed is exact arithmetic; the value on the other side of it is not, and nothing here estimates it. For the cost of keeping the car once it is yours, the tools under Keeping & Replacing are the ones that take that on.

Also excluded: your approval odds and your actual rate — this is not a credit offer and cannot tell you what you would be quoted; variable-rate and balloon contracts, since the arithmetic here assumes a fixed rate and equal payments; add-on products such as extended warranties, gap insurance and paint protection, which are commonly financed and which you should enter in the fees field if they are in your deal, because they carry interest for the whole term; extra payments and early payoff, which change the schedule; and how your state taxes a vehicle sale— several tax the price after the trade-in is deducted rather than before, which is why the tax is entered as a dollar figure off your buyer's order rather than computed from a rate we would have to guess.

Last reviewed: August 2026