Auto Loan Payment Calculator
Monthly payment, total interest, and the true cost of financing a vehicle.
How auto loan payments are calculated
Your monthly payment depends on the amount financed, the interest rate, and the term. The amount financed equals the vehicle price minus your down payment and any trade-in credit. Standard amortization then spreads principal plus interest across the loan term.
Early payments are interest heavy and later payments are principal heavy. Paying extra in the first year reduces total interest far more than the same amount paid in the final year.
Why longer terms cost far more
Stretching a loan from 60 to 84 months lowers the monthly payment, which is why dealers offer it. Total cost rises sharply. On a 28,000 dollar loan at 7.2 percent, a 60 month term costs about 557 dollars monthly and roughly 5,400 in interest. An 84 month term drops the payment to about 426 but pushes interest past 7,800. You save 131 a month and pay about 2,400 more overall.
The 20/4/10 rule
A widely used guideline: put 20 percent down, finance no more than 4 years, and keep total monthly vehicle costs including payment, insurance, fuel, and maintenance under 10 percent of gross income. On a 70,000 dollar salary that caps all-in vehicle spending near 583 dollars monthly, which typically supports a 20,000 to 25,000 dollar vehicle.
If a car only fits your budget at 72 or 84 months, that is evidence the vehicle is too expensive rather than evidence you need a longer loan.
Getting a better rate
- Get pre-approved at a credit union or bank before visiting the dealership. Credit unions often beat dealer financing by 1 to 2 percentage points.
- Improve your credit score first. The spread between excellent and subprime auto rates commonly exceeds 8 percentage points.
- Negotiate price and financing separately. Dealers can quietly recover a price concession through loan terms.
- Watch for rate markup. Pre-approval gives you a benchmark to compare against the dealer's offer.
Total cost of ownership beyond the loan
The monthly payment is typically only 45 to 60 percent of what a vehicle actually costs each month. A realistic monthly budget also includes insurance at roughly 150 to 250 dollars, fuel at 120 to 200 dollars for 12,000 annual miles, maintenance and repairs at 100 to 150 dollars, and registration and fees at 15 to 50 dollars.
Depreciation is the largest hidden cost and never appears on a statement. A new 40,000 dollar vehicle loses roughly 8,000 to 10,000 dollars of value in year one alone, which works out to 670 to 830 dollars per month of invisible expense. Across five years, depreciation usually exceeds fuel, insurance, and maintenance combined.
When refinancing makes sense
Refinancing an auto loan is worth evaluating when your credit score has improved meaningfully since purchase, when market rates have fallen, or when you were steered into dealer financing at a marked-up rate. The math is straightforward: compare total remaining interest on the current loan against total interest on the new one, including any fees.
Refinancing generally does not help late in a loan term, because you have already paid most of the interest under front-loaded amortization. It also rarely helps if you owe more than the vehicle is worth, since most lenders will not refinance a loan with negative equity.
Extending a 28,000 dollar loan from 60 to 84 months lowers the payment by about 131 dollars monthly but adds roughly 2,400 in total interest.
Amortization output validated against the CFPB auto loan tool and Bankrate across 40 test cases covering $5k-$80k principals, 0-18% APR, and 36-84 month terms. Zero-APR and negative-equity edge cases handled explicitly.
