How does the auto loan calculator work?
The calculator finds the amount you finance — the vehicle price, plus sales tax and fees, minus your down payment and trade-in — then spreads it over your term with the standard amortization formula. A $30,000 car with $3,000 down at 7% APR over 60 months works out to about $534.63 a month, with $5,077.94 in total interest. Each payment covers that month’s interest first, and the rest reduces the balance.
How do a down payment and trade-in change the payment?
Both cut what you borrow dollar for dollar, so both lower the monthly payment. A trade-in does one more thing: in most states sales tax is charged on the price after the trade-in is deducted. Trade in a $5,000 car against a $20,000 purchase in a 10% tax state and you are taxed on $15,000 ($1,500), not $20,000 ($2,000) — a $500 saving on tax alone, on top of the smaller loan.
Does a longer loan term cost more?
Yes. A longer term lowers the monthly payment but raises the total interest, because you owe the balance for longer. Financing $30,000 at 7%, a 60-month loan costs about $5,642 in interest, while stretching it to 84 months drops the payment but pushes interest to about $8,034 — roughly $2,400 more for the same car. Your APR matters even more: it depends mostly on your credit score, and ranges from about 5% for top-tier credit to over 15% for deep-subprime borrowers (Experian, Q1 2025).
How to calculate a car payment by hand
- 1
Enter the vehicle price. Use the out-the-door price before tax. A $30,000 car is the starting point.
- 2
Subtract your down payment and trade-in. Both lower what you borrow. $3,000 down on a $30,000 car leaves $27,000 to finance.
- 3
Add sales tax and fees. Most states tax the price after the trade-in credit, so a trade-in cuts the tax too.
- 4
Set your APR and term. The calculator amortizes the balance: $27,000 at 7% over 60 months is about $534.63 a month.
Auto loan reference tables
Average APR by credit score, plus how the monthly payment and total interest change with your term and rate.
Average auto loan APR by credit score
Your APR depends mostly on your credit score. These are the U.S. averages Experian reports for new and used car loans by credit tier (Q1 2025).
| Credit tier | Score range | New car APR | Used car APR |
|---|---|---|---|
| Super prime | 781–850 | 5.18% | 6.82% |
| Prime | 661–780 | 6.70% | 9.06% |
| Near prime | 601–660 | 9.83% | 13.74% |
| Subprime | 501–600 | 13.22% | 18.99% |
| Deep subprime | 300–500 | 15.81% | 21.58% |
| All buyers (average) | — | 6.73% | 11.87% |
Source: Experian, Average Car Loan Interest Rates by Credit Score (Q1 2025)
Monthly payment and interest by loan term ($30,000 at 7% APR)
A longer term lowers the monthly payment but raises the total interest. Here is $30,000 financed at 7% APR across common terms.
| Loan term | Monthly payment | Total interest |
|---|---|---|
| 36 mo (3 yr) | $926 | $3,347 |
| 48 mo (4 yr) | $718 | $4,483 |
| 60 mo (5 yr) | $594 | $5,642 |
| 72 mo (6 yr) | $511 | $6,826 |
| 84 mo (7 yr) | $453 | $8,034 |
Source: Socko calculation: standard amortization at the price ÷ term, with interest at APR ÷ 12.
Monthly payment and interest by APR ($35,000 over 60 months)
Your rate moves the payment as much as the price does. Here is $35,000 financed over 60 months at a range of APRs.
| APR | Monthly payment | Total interest |
|---|---|---|
| 4% | $645 | $3,675 |
| 6% | $677 | $5,599 |
| 8% | $710 | $7,580 |
| 10% | $744 | $9,619 |
| 12% | $779 | $11,713 |
| 14% | $814 | $13,863 |
Source: Socko calculation: 60-month amortization of $35,000 at each APR.
Frequently asked questions
How much is the monthly payment on a $30,000 car?
With $3,000 down at 7% APR over 60 months, you finance $27,000 and pay about $534.63/mo (≈ $5,078 total interest). With nothing down, it is about $594/mo.
What is a good interest rate on a car loan?
It tracks your credit score. In Q1 2025 the average was 6.73% APR on new cars and 11.87% on used (Experian). Top-tier credit averaged 5.18% new; deep-subprime averaged 15.81%.
Is a 72- or 84-month car loan a good idea?
It lowers the payment but costs more. On $30,000 at 7%, stretching from 60 to 84 months adds about $2,400 in interest and keeps you underwater longer. Pick the shortest term you can comfortably afford.
Does a trade-in lower my sales tax?
In most states, yes — tax is charged on the price after the trade-in. A $5,000 trade against a $20,000 car is taxed on $15,000. A few states (e.g. California, Virginia) tax the full price.
How much should I put down on a car?
A common rule is 20% down on a new car, 10% on used. More down means a smaller loan, lower payment, less interest, and less time spent underwater.
What is included in the amount financed?
It is the price plus tax and rolled-in fees, minus your down payment and trade-in. The calculator amortizes that figure, not the sticker price.
Is APR the same as the interest rate?
Not quite. The interest rate is the cost of the principal; the APR also folds in certain lender fees, so it is the truer cost. Compare loans by APR — that is what this calculator uses.
Is the auto loan calculator free, and is my data saved?
Yes — it is free and runs entirely in your browser. Nothing you enter is sent or stored.
This tool is for estimation and education, not financial advice. See our methodology for how these figures are calculated and sourced.