Auto Loan Calculator
Use this calculator to estimate your monthly car payment. Enter the vehicle price, down payment, trade-in value, loan term, and interest rate to see a complete breakdown of your auto loan costs including sales tax.
Most U.S. car buyers finance their purchase with an auto loan, and the monthly payment is almost always the number that drives the decision. That's a problem, because monthly payment is a deceptive lens — extending the loan term can shrink the payment while quietly inflating the total cost of the car by thousands of dollars.
This calculator computes monthly payment, total interest, and total cost using the standard amortization formula, but it also folds in the parts that often get ignored: sales tax on the purchase, trade-in credit, and down payment. It works for new and used vehicles, and the math applies equally to dealer financing, credit union loans, and bank loans.
Auto loans are typically much shorter than mortgages — most are 36 to 72 months — but rates are usually higher because cars depreciate fast and the collateral loses value quickly. Your credit profile drives most of the rate variation. A borrower with excellent credit might qualify for 4–5% APR; a subprime borrower on the same car might see 15%+.
Inputs
Results
Monthly Payment
$613.15
Loan Amount
$32,100.00
Total Interest
$4,688.84
Total Cost
$36,788.84
Cost Breakdown
Payment Schedule
| Month | Payment | Principal | Interest | Balance |
|---|---|---|---|---|
| 1 | $613.15 | $466.02 | $147.13 | $31,633.98 |
| 2 | $613.15 | $468.16 | $144.99 | $31,165.82 |
| 3 | $613.15 | $470.30 | $142.84 | $30,695.52 |
| 4 | $613.15 | $472.46 | $140.69 | $30,223.06 |
| 5 | $613.15 | $474.62 | $138.52 | $29,748.43 |
| 6 | $613.15 | $476.80 | $136.35 | $29,271.63 |
| 7 | $613.15 | $478.99 | $134.16 | $28,792.64 |
| 8 | $613.15 | $481.18 | $131.97 | $28,311.46 |
| 9 | $613.15 | $483.39 | $129.76 | $27,828.08 |
| 10 | $613.15 | $485.60 | $127.55 | $27,342.48 |
| 11 | $613.15 | $487.83 | $125.32 | $26,854.65 |
| 12 | $613.15 | $490.06 | $123.08 | $26,364.58 |
Formula
How to use this calculator
- Enter the negotiated vehicle price (not the MSRP, and not what is on the window sticker — what you actually agreed to pay).
- Enter your cash down payment.
- Enter your trade-in value if applicable. This is the dealer's offer for your old car, which reduces the financed balance.
- Enter your state/local sales tax rate. U.S. rates vary from 0% (Alaska, Delaware, Montana, New Hampshire, Oregon) to 10%+ in some metros.
- Choose a loan term. 60 months is the most common new-car term in the U.S.; 36 or 48 months saves interest; 72 or 84 months is increasingly common but creates negative-equity risk.
- Enter the APR you have been quoted. APR includes most fees and is the right number for monthly-payment math. Don't confuse it with the dealer's "money factor" — multiply that by 2400 to get APR.
- Compare scenarios. The biggest wins usually come from a larger down payment, a shorter term, or shopping the loan with a credit union or bank before going to the dealer.
Worked examples
New car, good credit
Vehicle: $35,000 Down payment: $5,000 Trade-in: $0 Sales tax: 6% Loan: $31,800 at 5.5% APR for 60 months Monthly payment: ≈ $607 Total interest: ≈ $4,638 Total cost: ≈ $40,638 Roughly $1.16 of total cost for every $1 of vehicle, after tax.
Same car, stretched to 84 months
Same $31,800 loan, but at 84 months instead of 60. Monthly payment: ≈ $458 (a tempting $149/month "savings") Total interest: ≈ $6,672 Total cost: ≈ $42,672 The longer term saves $149/month but adds $2,034 to total interest — and you'll likely owe more than the car is worth for the first 3–4 years (negative equity).
Subprime impact
Same $31,800 loan, 60-month term, but at 15% APR instead of 5.5%. Monthly payment: ≈ $757 Total interest: ≈ $13,604 Total cost: ≈ $50,604 The same car costs about $10,000 more over the life of the loan because of credit-score-driven rate differences. This is why improving credit before financing a car can save more than negotiating a few hundred off the price.
When to use this calculator
Use this calculator before you visit the dealer, not after. The single best move in auto financing is to walk in with a pre-approved loan offer from a credit union, bank, or online lender — then let the dealer try to beat it. Dealers make significant profit on financing markups, so even a small rate concession from them confirms you had a strong opening number.
It's also useful for "buy vs lease" thinking. Compare the total cost computed here with the total of monthly lease payments plus any fees and residual buyout. For that comparison directly, use the lease-vs-buy calculator.
This calculator assumes a fixed-rate, simple-interest loan, which describes the vast majority of U.S. auto loans. Some subprime lenders use precomputed interest or "Rule of 78" structures that penalize early payoff; those are uncommon but worth flagging in your loan paperwork.
Common mistakes to avoid
- Focusing only on monthly payment. Dealers can hit almost any monthly target by lengthening the term — the question is total cost.
- Confusing the money factor (used in leases) with APR. APR ≈ money factor × 2400. A "0.0025 money factor" sounds tiny but is actually 6% APR.
- Rolling negative equity from a previous loan into the new one. This stacks debt onto a depreciating asset and is the fastest way to spend a decade upside-down.
- Skipping the credit-union step. Credit unions and online lenders consistently offer lower auto-loan rates than dealer financing, often by 1–3 percentage points.
- Not separating the trade-in negotiation from the purchase price. Dealers can inflate one and shrink the other to give the illusion of a deal. Negotiate each independently.
- Adding dealer add-ons (extended warranty, GAP insurance, paint protection) to the financed amount. These products mark up the loan AND pay interest on the markup. If you want them, pay cash or buy them elsewhere.
Frequently Asked Questions
Sources & further reading
- Auto loans: shopping for the best deal — U.S. Consumer Financial Protection Bureau
- Understanding vehicle financing — U.S. Federal Trade Commission
- Auto loan delinquency and credit access data — Federal Reserve Bank of New York