Auto Loan Calculator
See your estimated monthly payment, total interest, and total cost for any car loan.
Built and maintained by Jefferson Almeida · Last updated
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Your loan estimate
How car loan payments are calculated
An auto loan is an amortizing loan: a fixed monthly payment where the split between interest and principal shifts over time. Early payments are interest-heavy; later payments are principal-heavy.
The monthly payment formula:
M = P × [r(1+r)ⁿ] / [(1+r)ⁿ − 1]
Where P is the amount financed, r is the monthly rate (annual APR ÷ 12), and n is the number of months.
On a $30,000 loan at 7% for 60 months, the payment is about $594, and total interest is roughly $5,642.
What the loan term does to your total cost
Stretching the term lowers the payment and raises the total cost. On that same $30,000 at 7%:
| Term | Monthly payment | Total interest |
|---|---|---|
| 36 months | $926 | $3,347 |
| 48 months | $718 | $4,483 |
| 60 months | $594 | $5,642 |
| 72 months | $511 | $6,826 |
| 84 months | $453 | $8,034 |
Going from 36 to 84 months cuts the payment roughly in half - and more than doubles the interest.
The 84-month problem: long loans plus fast depreciation is how people end up underwater. A new car typically loses 20% of its value in year one and roughly 60% by year five. On an 84-month loan you may owe more than the car is worth for the first four years, which means an accident or a needed trade-in leaves you paying off a car you no longer have.
The costs that aren't in the sticker price
Dealer financing worksheets often bundle these in, which is why the amount financed exceeds the price you negotiated:
- Sales tax - varies by state, often 4–8% of the purchase price (the sales tax calculator has 2026 rates by state)
- Title, registration, and documentation fees - $100–800 depending on state
- Extended warranty or service contract - frequently high-margin and negotiable
- GAP insurance - covers the gap between what you owe and what insurance pays if the car is totaled; genuinely useful on long loans, but usually cheaper from your own insurer than the dealer
- Negative equity rolled from a trade-in - this is the one that quietly wrecks people
Because several of these are financed rather than paid upfront, the rate on the contract understates what the loan costs you. The APR calculator converts rate-plus-fees into the single number worth comparing between lenders.
How to actually reduce what you pay
Get pre-approved before you shop. A credit union or bank pre-approval gives you a rate to beat and converts you into a cash buyer at the dealership. Dealer financing can be competitive, but you can only know that with a comparison in hand.
Negotiate the price, not the payment. "What monthly payment are you looking for?" is a question designed to move the conversation away from total cost. Any payment target can be hit by extending the term.
Watch the credit tier. Rates vary enormously by score - a buyer at 780 and a buyer at 620 might be quoted 5% and 14% on the same car. On a $30,000 60-month loan, that's a difference of about $8,000.
Consider a larger down payment. Beyond reducing the amount financed, 20% down on a new car substantially reduces the time spent underwater.
FAQ
Does this include title, registration, or dealer fees?
No - this calculator covers vehicle price, sales tax, down payment, and trade-in only. Title, registration, and documentation fees vary by state and dealer and would add a small amount to your financed total.
Should I choose a longer loan term for a lower payment?
A longer term lowers your monthly payment but increases total interest paid and increases the risk of being "upside down" (owing more than the car is worth) for longer. Shorter terms cost more per month but less overall.
Is a longer loan ever the right choice?
Occasionally - if the rate is very low (0–2% promotional financing) and you'd genuinely invest the payment difference. At 7%+ it's almost always a mistake.
Should I put a car purchase on a 0% promotional APR?
Those offers are usually in lieu of a cash rebate, not in addition to it. Compare the total cost of "0% financing" against "rebate plus your own credit union loan" - the second frequently wins.
💡 Did you know?
Buying a car on credit wasn't really an option until 1919, when General Motors created GMAC (General Motors Acceptance Corporation) to finance its own customers. Early loans looked nothing like today's - buyers typically needed a large down payment, often around a third of the price, with the balance due within a year. That access to credit was a major reason car ownership went from a luxury to a mainstream reality for American households within a decade.