Free Auto Loan Calculator

Understanding your car loan

The sticker price is rarely what you actually finance. Sales tax gets added, your down payment and trade-in get subtracted, and the result — not the price on the window — is what your interest rate applies to. Getting that number right is most of getting the payment right.

How the amount financed is built

Your loan balance starts from the vehicle price, then adds sales tax and subtracts anything you put down:

• Sales tax is calculated on the price minus your trade-in value in most states, which is why a trade-in often saves you more than its face value.
• Down payment reduces the balance dollar for dollar and lowers every payment that follows.
• Trade-in equity works the same way as cash down, with the added tax benefit above.

Dealer fees, extended warranties, and gap insurance are often rolled into the financed amount too. This calculator doesn't include them, so if you're quoted a payment that's higher than what you see here, added products are a common reason.

Where your payment actually goes

Car loans amortize like any other fixed loan: interest is charged on the current balance, and whatever's left of your payment reduces the principal. In the example above, the first $667.21 payment splits roughly $185 to interest and $483 to principal — about 72% goes to the balance.

That ratio is far friendlier than a mortgage's, because the term is short and the balance falls quickly. It also means auto loans reward extra payments less dramatically than long-term debt does — there's simply less future interest to cancel.

Why the loan term matters more than it looks

Stretching the term lowers the payment but raises the total cost. Financing that same $34,100 over 72 months instead of 60 drops the payment to about $573 — roughly $94 less per month — but total interest rises from $5,932 to about $7,172. You'd pay around $1,240 more for the same car.

The longer risk is being underwater: owing more than the vehicle is worth. Cars depreciate fastest in the first few years, so a long term means the balance falls slower than the value does. If the car is totaled or you need to sell during that window, the gap comes out of your pocket unless you carry gap coverage.

What extra payments do here

Adding $100 a month to the example loan pays it off in about 51 months instead of 60 and saves roughly $915 in interest. That's a real saving, but notice the scale relative to a mortgage — short terms and moderate rates limit how much extra payments can compound.

If you do pay extra, confirm your lender applies it to principal rather than treating it as an early payment toward next month, and check whether the loan carries a prepayment penalty. Some subprime auto contracts do.

Common mistakes when financing a car

• Shopping by monthly payment. Any payment can be reached by extending the term. Negotiate the price first, then the financing, as separate conversations.
• Forgetting tax, title, and registration. Sales tax alone was $2,100 in the example.
• Accepting dealer financing without comparing. A rate quote from your own bank or credit union first gives you something to measure against.
• Rolling negative equity forward. Financing what you still owe on a trade-in adds it to the new loan and compounds the problem.
• Budgeting only the payment. Insurance, fuel, maintenance, and registration are ongoing costs the loan doesn't cover.

What this calculator doesn't include

This estimates principal and interest based on the amount financed. It doesn't model dealer fees, documentation charges, extended warranties, gap insurance, or manufacturer rebates and promotional financing. Sales tax rules also vary — a few states tax the full price regardless of trade-in, and some localities add their own rate on top.

It also assumes a fixed rate and equal payments for the full term. For the actual figure, ask the dealer or lender for the loan's APR and total finance charge in writing, which makes competing offers directly comparable.