Estimates for planning only. Sales tax is applied to the price after trade-in credit, which is common but varies by state; title, registration, and dealer fees are not included. This is general education, not financial advice.
New for 2025–2028: deduct your car-loan interest
A 2025 federal tax law lets many buyers deduct the interest on a new-car loan — up to $10,000 per year for tax years 2025 through 2028. It's an "above-the-line" deduction, so you can claim it even if you don't itemize.
To qualify, the vehicle generally must be new, have its final assembly in the U.S., and be bought with a loan taken out after Dec 31, 2024. The deduction phases out above $100,000 income (single) / $200,000 (married filing jointly), and disappears around $150k / $250k. Confirm the car's assembly location on the window sticker (the "final assembly point" line) and check current rules with a tax professional.
How your car payment is calculated
Four numbers decide your monthly payment: how much you finance, your interest rate, and how long you borrow. This calculator starts from the vehicle price, adds estimated sales tax, then subtracts your down payment and trade-in to find the amount financed. It then applies the standard amortization formula at your APR over your chosen term so the loan pays off to zero at the end.
The trap most buyers fall into is shopping by the monthly payment alone. A dealer can hit almost any monthly number by stretching the loan to 72 or 84 months — but that quietly adds thousands in interest. Always look at the total interest and total of payments, not just the monthly figure.
What changes your payment the most
- Loan term. Longer terms lower the monthly payment but raise total interest and keep you in debt longer. 48–60 months is a sensible ceiling for most buyers.
- Down payment. Every dollar down is a dollar you don't finance — it cuts both your payment and your interest, and helps you avoid being upside-down.
- Interest rate (APR). Driven mostly by your credit score and whether the car is new or used. A few points of APR can mean thousands over the life of the loan.
- Trade-in. Reduces the amount financed and, in most states, the taxable amount too.
- Price. The obvious one — negotiate the out-the-door price first, before talking monthly terms.
New vs. used — and your interest rate
Used-car loans almost always carry higher interest rates than new-car loans, and rates climb as credit scores fall. If your credit is strong, a new-car promotional rate can occasionally beat a used-car rate — but a slightly used car still usually wins on total cost because someone else absorbed the steep first-year depreciation.
The single best move before shopping: get pre-approved by your own bank or credit union. You'll know your real rate, you can plug it in here, and you can use it as leverage if the dealer's financing isn't better.
Pay it off faster
- Round up your payment. Even an extra $25–$50 a month goes straight to principal and trims interest and term.
- Make a mid-year lump payment. A tax refund or bonus applied to principal has an outsized effect early in the loan.
- Keep the term short. Choosing 48 months over 72 saves real money even though the monthly is higher.
- Refinance if rates drop or your credit improves — a lower APR on the remaining balance can reduce your payment with no extra cash down.
Before paying extra, confirm with your lender that additional payments apply to principal and that there's no prepayment penalty.