Auto Loan Calculator — Monthly Car Payment & Total Interest

Estimate your monthly car payment, total interest, and total cost from price, down payment, trade-in, sales tax, APR, and term — with a 36–72 month comparison table.

Auto Loan Calculator — Monthly Car Payment & Total Interest | syedwaleed.com

Know Your True Monthly Car Payment Before You Sign

Enter the vehicle price, down payment, trade-in, sales tax, APR, and term to get your exact monthly payment, total interest, and total cost — plus a side-by-side comparison of 36, 48, 60, and 72-month loans.

Loan term
Estimated monthly payment
—
—
Loan amount financed
—
Sales tax paid
—
Total interest
—
Total of loan payments
—
Down + trade-in
—
Total cost of the car
—
Term comparison — same car, different loans
TermMonthly paymentTotal interest

Estimate only — dealer fees, registration, and lender fees vary. Sales tax is calculated on (price − trade-in), which is how most US states credit a trade-in. Not financial advice.

100% Private

Your prices, APR, and loan details are calculated in your browser and never sent anywhere.

No Signup

No email, no account, no dealer calling you later. Run the numbers freely.

Free Forever

Unlimited calculations, comparisons, and what-if scenarios at zero cost.

How to Use the Auto Loan Calculator

  1. 1Enter the car details

    Type the vehicle price, your down payment, and trade-in value. Add your state’s sales tax rate — the calculator credits the trade-in, like most US states do.

  2. 2Set APR and term

    Enter the annual percentage rate the lender quoted you, then tap a term (36, 48, 60, or 72 months) or type a custom term.

  3. 3Read your real numbers

    You’ll get the monthly payment, loan amount financed, total interest, and the all-in total cost of the car — not just the sticker price.

  4. 4Compare the terms

    The comparison table shows what the same car costs at 36/48/60/72 months. Longer terms lower the payment but raise total interest — check the trade-off before you sign.

Why This Calculator Helps You Buy Smarter

True amortization math

Uses the standard US loan amortization formula — not a flat estimate — so the monthly payment matches what a bank’s own calculator produces.

Trade-in tax credit

In most states you only pay sales tax on price minus trade-in. We model that, which can save you hundreds versus calculators that tax the full price.

Term comparison table

See monthly payment and total interest for 36, 48, 60, and 72 months side by side — the fastest way to see what a “low payment” really costs you.

Total cost, not just payment

Dealers sell on monthly payments. We show total interest and the all-in cost of the car so you negotiate on the number that actually matters.

Zero-APR friendly

Promotional 0% APR offers are handled correctly (payment = principal ÷ months), so you can compare a 0% deal against a cash-back offer honestly.

Private and instant

Everything runs client-side — adjust any number and the results update immediately, with no data leaving your device.

Auto Loan FAQs

How is the monthly car payment calculated?
The standard amortization formula: payment = P × r(1+r)n ÷ ((1+r)n − 1), where P is the loan amount, r is the monthly rate (APR ÷ 12), and n is the number of months. With 0% APR the formula simplifies to P ÷ n. This is the same formula US banks and credit unions use.
Is a longer loan term (72 or 84 months) a bad idea?
It depends on the trade-off. A longer term cuts your monthly payment but increases total interest — sometimes by thousands. It also raises the risk of going “upside down” (owing more than the car is worth) since cars depreciate fast. Use the comparison table above to see exactly what each extra year costs you in interest.
How much down payment should I make?
The long-standing rule of thumb is 20% down on a new car and 10% on used, which keeps the payment manageable and protects against depreciation. A bigger down payment also shrinks the loan amount, so you pay less interest overall.
Does my trade-in really lower sales tax?
In most US states, yes: you pay sales tax on the price minus the trade-in value. A few states (like California and Virginia in most cases) don’t allow the credit, so this calculator may slightly underestimate tax there. Check your state’s rule if it matters for your budget.
APR vs. interest rate — what’s the difference?
For auto loans they’re usually quoted the same way, but technically APR includes certain lender fees while the “interest rate” is just the cost of borrowing. When comparing offers, compare APR to APR — it’s the more complete number.
Should I take 0% APR or a cash rebate?
Do the math both ways. Run this calculator with 0% APR and the full price, then again with the rebate subtracted from the price at the normal APR. Whichever gives the lower total cost wins — for short terms the 0% offer usually wins, for long terms the rebate often does.
Is this financial advice?
No. This is a math tool that estimates payments from the numbers you enter. Dealer fees, registration, title, and lender-specific fees vary. For decisions about your finances, talk to a qualified professional.

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