Auto Loan Calculator (2026) – Car Payment with Trade-In, Tax & Down Payment
Get your true monthly car payment — including trade-in deduction, down payment, and sales tax. Built for new and used vehicles in 2026, with a 2026 rate guide, affordability check, and the 20/4/10 rule explained.
How to Use This Auto Loan Calculator
- Enter the full vehicle price. Use the negotiated purchase price — not the sticker price. If you haven't negotiated yet, use the MSRP as a starting point. Do not subtract your trade-in or down payment here; the calculator handles those separately.
- Enter your down payment and trade-in value. Both reduce the amount you need to finance. Your trade-in value is the amount the dealer agrees to credit toward the new purchase — get at least 3 quotes (Carmax, KBB, Carvana) before accepting a dealer offer.
- Add your state's sales tax rate — and check the trade-in rule. In most US states (41-43 of them), sales tax is calculated on the price after your trade-in is deducted. A few states — California, Virginia, Hawaii, DC, and Michigan (capped) — tax the full price regardless of trade-in. Use the toggle to match your state, and enter 0% if your state has no vehicle sales tax at all.
- Enter the APR and select your loan term. Use the rate from your pre-approval letter. In 2026, new car rates for good-credit borrowers (720+ FICO) run 5%–9%; used car rates run 8%–14%. 60 months is the most common term — 48 months saves more in total interest.
- Optionally add your monthly income for an affordability check. The 20/4/10 rule recommends keeping your car payment under 10% of gross monthly income. The calculator will show your payment as a percentage and flag if it exceeds the guideline.
Auto Loan Interest Rates in 2026
Use these benchmarks to pre-fill the calculator before you have a formal lender quote. Your actual rate depends on credit score, lender type, vehicle age, and loan term.
New Car Loan Rates by Credit Score (2026)
| Credit Score | Rating | Typical APR Range |
|---|---|---|
| 750+ | Excellent | 5.0%–6.5% |
| 720–749 | Very Good | 6.0%–7.5% |
| 680–719 | Good | 7.0%–9.0% |
| 620–679 | Fair | 10.0%–14.0% |
| 580–619 | Poor | 15.0%–19.0% |
| Below 580 | Very Poor | 20.0%–29.0%+ |
Used Car Loan Rates by Credit Score (2026)
| Credit Score | Rating | Typical APR Range |
|---|---|---|
| 750+ | Excellent | 7.0%–8.5% |
| 720–749 | Very Good | 8.0%–10.0% |
| 680–719 | Good | 10.0%–13.0% |
| 620–679 | Fair | 14.0%–18.0% |
| Below 620 | Poor/Subprime | 19.0%–25.0%+ |
Dealer Financing vs. Bank or Credit Union
Credit unions consistently offer the lowest auto loan rates — often 0.5%–1.5% below bank rates for the same credit profile. Get pre-approved before visiting any dealer. Dealer financing can be competitive (and sometimes offers 0% APR promotions on new vehicles), but dealers can also mark up rates for profit — a practice called "dealer reserve." Always compare any dealer offer to your pre-approval rate before signing.
Worked Example: $35,000 SUV with $5,000 Down and $4,000 Trade-In
Here's how the numbers break down for a typical 2026 mid-size SUV purchase, assuming a state that applies the trade-in tax credit (the majority case):
| Input | Value |
|---|---|
| Vehicle Price | $35,000 |
| Taxable Amount (price − trade-in) | $31,000 |
| Sales Tax (6.5% of taxable amount) | $2,015 |
| Down Payment | −$5,000 |
| Trade-In Value | −$4,000 |
| Amount Financed | $28,015 |
| APR | 7.49% |
| Loan Term | 60 months |
| Result | Amount |
|---|---|
| Monthly Payment | $561.23 |
| Total Interest Paid | $5,658.80 |
| Total of Payments | $33,673.80 |
| True Cost (down + payments) | $38,673.80 |
Now compare: if the buyer stretched to a 72-month term at the same rate, the monthly payment drops to $484.25 — but total interest jumps to $6,850.77, costing $1,191.97 more for the convenience of a lower monthly bill.
In a state that doesn't give a trade-in tax credit (like California or Virginia), the same purchase is taxed on the full $35,000 instead of $31,000 — $260 more in tax at 6.5%, which flows straight into the financed amount and the monthly payment.
How Much Car Can You Afford? The 20/4/10 Rule
The 20/4/10 rule is the most widely cited personal finance guideline for car buying. It helps you avoid overspending on a depreciating asset:
Put at least 20% down to avoid immediately being underwater. Cars depreciate 15%–20% in the first year — a small down payment means you owe more than the car is worth on day one.
Finance for no more than 4 years (48 months). Longer terms (72–84 months) dramatically increase total interest and leave you upside-down far longer than the car's reliable service life.
Keep your total monthly car payment (loan + insurance) under 10% of gross monthly income. Above 15%, your budget is under significant strain — especially if you carry other debt.
Real-world application: On a $6,000/month gross income, the 10% rule means a maximum car payment of $600/month. At 7.49% APR over 48 months with 20% down, that means a target vehicle price of around $29,000.
Frequently Asked Questions About Auto Loans
What is the average auto loan interest rate in 2026?
New car rates for borrowers with good credit (720+ FICO) average 5.5%–8.5% APR. Used car loans run higher: 8%–14% for good credit, 15%–22%+ for fair or rebuilding credit. Credit unions typically offer the lowest rates, followed by banks, then dealership financing.
Should I include sales tax in my auto loan?
In most US states, your trade-in value is deducted from the taxable amount before sales tax is calculated (a "trade-in tax credit"). A handful of states — California, Virginia, Hawaii, DC, and Michigan (capped) — tax the full price regardless of trade-in. Either way, sales tax is often rolled into the financed amount, so you pay interest on it for the full term. Pay sales tax upfront if possible — it saves money. Use the trade-in tax toggle above to match your state's rule.
Does a trade-in reduce my loan amount?
Yes — your trade-in value directly reduces the amount you finance. If your trade-in is worth more than you owe (positive equity), the full trade-in value reduces the new loan. If you owe more than it's worth (negative equity / "underwater"), that deficit is typically rolled into the new loan, increasing your financed amount.
What is the 20/4/10 rule for buying a car?
The 20/4/10 rule: put at least 20% down, finance for no more than 4 years (48 months), and keep total auto expenses under 10% of gross monthly income. Following this protects against going upside-down and keeps auto costs from straining your budget.
Is a 72-month or 84-month car loan a bad idea?
Longer terms lower monthly payments but cost significantly more in total interest — often $2,000–$6,000 extra on a typical purchase. They also leave you underwater (owing more than the car is worth) for years. Most advisors recommend 48–60 month terms as the best balance.
Should I finance through a dealer or my own bank?
Get pre-approved through your bank or credit union before visiting any dealership. This gives you a rate benchmark and negotiating leverage. Dealer financing can be competitive (especially 0% APR promotions on new cars), but dealers can mark up rates for profit. Always compare before signing.
How much should I put down on a car?
Financial experts recommend at least 20% on a new car and 10% on a used car. This reduces the financed amount, lowers your monthly payment, and prevents being underwater immediately. On a $35,000 car, 20% down means financing only $28,000.
What credit score do I need for a good auto loan rate?
To qualify for the best new car rates in 2026 (under 7% APR), aim for a credit score of 720 or higher. Scores of 660–719 typically see 7%–10%. Below 620 (subprime) usually means 15%–22%+. Even a 1% rate difference on a $30,000 loan saves roughly $500 over 5 years.