Auto Loan Calculator
Get your exact monthly car payment including sales tax, dealer fees, trade-in value and negative equity. Includes GAP insurance advisor, equity tracker, new vs. used comparison, refinance analysis — all calculated live as you type.
Rec: 20%+ new · 10%+ used
Manufacturer / dealer incentive
KBB / Edmunds estimate
Remaining loan balance
New car avg: ~6.8% (Mar 2026)
US avg ~7% · AK/DE/MT/NH/OR = 0%
Avg $200–$900 by state
What Is an Auto Loan Calculator?
An auto loan calculator is a financial tool that computes your exact monthly car payment based on the vehicle's price, your down payment, the loan's interest rate (APR), and the repayment term. More advanced versions — like the CatchyTools Auto Loan Calculator above — also factor in sales tax, dealer fees, trade-in value, negative equity, and even model how a car's value depreciates against your loan balance over time.
The core formula behind every auto loan calculator is the standard amortization equation: M = P × [r(1+r)^n] ÷ [(1+r)^n – 1], where M is monthly payment, P is the loan principal, r is the monthly interest rate (APR ÷ 12), and n is the total number of payments. This produces a fixed monthly payment where the proportion of interest versus principal shifts with every payment — a concept called amortization.
Why most online auto loan calculators fall short: The average calculator on Bankrate or NerdWallet shows you a monthly payment — and that's it. The CatchyTools version goes five levels deeper: Standard mode for real-world out-the-door pricing, New vs. Used comparison, an Equity Tracker to visualize when you stop being underwater, a Refinance analyzer, and an Affordability mode that works backward from your budget to find your maximum car price.
What Makes This Calculator Different from Competitors
After analyzing the top-ranking auto loan calculators on Bankrate, NerdWallet, Edmunds, Calculator.net, and U.S. News — here's what they typically miss that this one includes:
Shows year-by-year whether your loan balance exceeds the car's market value — and exactly when you cross into positive equity. No major competitor offers this in a single auto loan tool.
Automatically detects when your down payment is under 20% or term exceeds 60 months, and flags the need for GAP insurance with cost guidance. Competitors ignore this entirely.
Detects when trade-in owed exceeds trade-in value and warns you that rolling this into a new loan is financially dangerous — with a clear explanation of why.
Live feedback on whether your purchase meets the financial advisor standard of 20%+ down, 48-month or shorter term, and total costs at or below 10% of income.
Enter your monthly income and the calculator works backward — factoring in insurance, fuel, and maintenance — to tell you the maximum car price you can actually afford.
How Auto Loan Payments Are Calculated
Auto loan payments are calculated using standard amortization. The lender takes your loan amount (vehicle price minus down payment, plus taxes and fees if financed), applies a monthly interest rate, and computes a fixed payment that will bring the balance to exactly zero on the final payment date. Every payment covers that month's interest first, with the remainder reducing principal.
What Goes Into Your Loan Amount
Most buyers are surprised to find their actual loan is much larger than the sticker price. Here is what typically gets rolled into the financed amount: vehicle price minus down payment, minus trade-in credit, plus any negative equity from the trade-in, plus sales tax (in most states), plus dealer documentation fees ($200–$900), plus title and registration fees ($200–$500). On a $35,000 vehicle with 7% sales tax, $400 in doc fees, and $300 in registration, the taxable amount adds $2,450 — bringing the financed amount to roughly $30,150 after a $7,000 down payment.
The 84-month trap: Stretching an auto loan to 84 months (7 years) keeps the monthly payment low but dramatically increases total interest paid and keeps you underwater on the vehicle for years. The average monthly car payment for a new car reached $772 in the fourth quarter of 2025, while 20.3% of new car buyers now have payments over $1,000. Many of these buyers chose long terms to manage the payment — not the total cost. Always check the all-in column in the results panel.
New vs. Used — The Real Rate Difference
In January 2026, the average car loan interest rate was 6.8% APR for new car loans and 10.5% APR for used car loans, according to Edmunds. That 3.7-point spread means a $22,000 used car loan over 36 months costs approximately $1,780 more in interest than a $22,000 new car loan — even though the used car is cheaper. The New vs. Used mode in this calculator shows the full side-by-side comparison including tax, fees, and all-in cost.
Auto Loan Sales Tax — State-by-State Rules
Sales tax on vehicle purchases varies dramatically by state and is one of the most misunderstood costs in auto financing. Five states charge no sales tax at all. Most states charge tax on the full purchase price. And many states offer a trade-in credit — you only pay tax on the difference between the new car price and your trade-in value, which can save hundreds or even thousands of dollars.
| State Rule | States | Example: $35K car / $10K trade-in | Tax at 7% |
|---|---|---|---|
| No sales tax | AK, DE, MT, NH, OR | $0 tax | $0 |
| Tax on price minus trade-in | Most US states | Tax on $25,000 | $1,750 |
| Tax on full price (no trade-in credit) | CA, DC, HI, KY, MD, MI, MT, VA | Tax on $35,000 | $2,450 |
The difference between a state with trade-in tax credit and one without it is $700 on this example — a real factor in the rent vs. buy decision if you live near a state line. Some states do not offer any sales tax reduction with trade-ins, including California, District of Columbia, Hawaii, Kentucky, Maryland, Michigan, Montana, and Virginia. Always enter your state's rate into the calculator for an accurate number.
Rebates and taxes: Cash rebates from manufacturers are taxed differently by state. In many states, tax is calculated on the full pre-rebate price — meaning a $2,000 rebate doesn't reduce your tax bill at all. States that do not tax rebates include Arizona, Iowa, Kansas, Minnesota, Missouri, Nebraska, Texas, and Wyoming, among others. Always confirm your state's rule before finalizing numbers.
Trade-Ins and Negative Equity — The Most Dangerous Auto Finance Trap
A trade-in is the vehicle you give the dealer as partial payment toward a new car. If you owe less on the trade-in than it's worth, that positive equity reduces your new loan. If you owe more than it's worth — which is called being underwater or having negative equity — the dealer will roll that extra amount into your new loan. You are now financing your new car plus the unpaid balance of your old one.
Why negative equity is so common: A new car drops roughly 20% in value during the first year alone. Long loan terms of 72 or 84 months make the problem worse because early payments go mostly toward interest, not the principal balance. A buyer who puts 0% down on a $35,000 vehicle with a 72-month loan still owes about $27,000 after a full year — while the car is worth roughly $28,000. Any unexpected need to trade in or sell during the first two years can easily result in negative equity.
How to Avoid or Minimize Negative Equity
The most effective strategies are: make a down payment of at least 20% to start ahead of depreciation; choose a term of 48 months or less to pay down principal faster; do not roll negative equity from one loan into the next; and get your trade-in value from multiple sources (CarMax, Carvana, KBB, Edmunds) before accepting the dealer's offer. The Equity Tracker mode in this calculator shows you exactly when your loan balance crosses below your car's value — and how large the underwater gap is in each year.
GAP Insurance — Do You Need It?
GAP insurance (Guaranteed Asset Protection) covers the difference between what your standard auto insurance pays out (the car's actual cash value at the time of the loss) and what you still owe on your auto loan. If your car is totaled in a crash or stolen, standard insurance pays market value. If your loan balance is higher — which is common in the first 1–3 years — you're responsible for the difference out of pocket.
| Scenario | Car's Market Value | Loan Balance | Without GAP | With GAP |
|---|---|---|---|---|
| Year 1, 0% down, 72-mo loan | $28,000 | $33,500 | You owe $5,500 | $0 out of pocket |
| Year 2, 10% down, 60-mo loan | $24,000 | $25,800 | You owe $1,800 | $0 out of pocket |
| Year 3, 20% down, 48-mo loan | $21,000 | $18,200 | No gap — positive equity | Not needed |
Where to buy GAP insurance: Consider GAP insurance if you put less than 20% down, have a loan term over 60 months, or bought a vehicle that depreciates quickly. Your auto insurer often offers gap coverage cheaper than dealer financing. Through your existing insurer, GAP coverage typically costs $20–$40 per year. Dealers often mark it up to $400–$900 as a one-time add-on. Always buy it from your insurer, not the dealership F&I office.
The 20/4/10 Rule — The Smartest Car Buying Formula
The 20/4/10 rule is the most widely cited guideline for responsible auto financing. It sets three simple limits: put at least 20% down, keep the loan term to 4 years (48 months) or less, and keep total car expenses — payment, insurance, fuel, and maintenance — at no more than 10% of your gross monthly income.
This rule exists because it keeps three dangerous problems in check simultaneously. A 20% down payment ensures you never start underwater. A 4-year term means you build equity faster than most cars depreciate. And capping car costs at 10% of income prevents what financial planners call "car poverty" — the situation where vehicle expenses crowd out savings, investing, and emergency funds.
Reality check: Most Americans cannot afford the car they buy by the 20/4/10 standard. The average loan amount for new cars hit $43,759 at the end of 2025, with average monthly payments of $772. For the 20/4/10 rule to work at that price point, a buyer would need gross monthly income of at least $7,720 — roughly $92,640 per year. Use the Affordability mode in the calculator to find your real number before stepping into a dealership.
Auto Loan Rates by Credit Score — March 2026
Your credit score is the single biggest factor in the rate you'll be offered — and the difference between excellent and fair credit is not trivial on a car loan. On a $30,000, 60-month loan, moving from a 640 score to a 760 score can reduce your monthly payment by over $100 and cut total interest by $5,000+.
| Credit Score | Category | New Car APR (est.) | Used Car APR (est.) | $30K · 60 mo Monthly |
|---|---|---|---|---|
| 781–850 | Super Prime | 4.5%–6.5% | 6.0%–8.5% | ~$558–$580 |
| 661–780 | Prime | 6.5%–9.0% | 9.0%–12.0% | ~$580–$623 |
| 601–660 | Near Prime | 9.0%–14.0% | 12.0%–18.0% | ~$623–$699 |
| 501–600 | Subprime | 14.0%–20.0% | 18.0%–25.0% | ~$699–$800 |
| 300–500 | Deep Subprime | 20.0%–30.0%+ | 25.0%–36.0%+ | ~$800–$1,000+ |
Even improving your score by 40–60 points before applying can move you into a better tier and save thousands. Check your free credit report at AnnualCreditReport.com, pay down revolving debt below 30% utilization, and dispute any errors — these are the fastest ways to boost your score before a major loan application.
When to Refinance Your Auto Loan
Refinancing an auto loan means taking out a new loan to pay off the existing one — ideally at a lower interest rate, reducing your monthly payment and total interest cost. Unlike mortgage refinancing, auto loan refinancing typically has zero fees, making it an almost risk-free calculation when rates or your credit situation has improved.
Best Times to Refinance
Refinancing makes the most financial sense when: (1) market rates have dropped at least 1–2 percentage points since you took out your original loan; (2) your credit score has improved significantly since origination, qualifying you for a better tier; (3) you financed through a dealership and suspect the dealer marked up your rate; or (4) you want to change your term — either shorter to pay off faster, or longer to reduce monthly cash flow pressure. Use the Refinance mode in the calculator to model the exact monthly savings and total interest impact for your scenario.
When not to refinance: Avoid refinancing if you're more than halfway through your loan term (most remaining payments are principal at that point), if the new loan extends your term by years, or if your car has depreciated to the point where you're underwater — refinancing while underwater can make the situation worse. Always run the full break-even analysis in the Refinance mode.
Related Financial Calculators
Auto loans don't exist in isolation. These companion tools help you manage the full picture of vehicle ownership and personal debt:
Compare auto loans vs. personal loans side by side. Model early payoff, true APR vs. stated rate, and debt consolidation — all in one tool. Great for buyers considering an unsecured personal loan instead of dealer financing.
High credit card balances raise your debt-to-income ratio and lower your credit score — both of which increase your auto loan rate. Pay down cards before applying for a car loan to qualify for a better tier.
Buying a home and a car at the same time? Understand all closing costs for your mortgage — because financing a vehicle before closing can affect your mortgage approval if it changes your debt-to-income ratio.
Frequently Asked Questions
An auto loan is a secured installment loan used to purchase a vehicle. The lender pays the dealer for the car, and you repay the lender over a set term — typically 24 to 84 months — with interest. The car serves as collateral, meaning the lender can repossess it if you stop making payments. Each monthly payment covers the interest accrued on the remaining balance plus a portion of the principal. In the early months, most of the payment goes to interest; by the final months, nearly all of it reduces the principal. This is standard loan amortization.
The average auto loan interest rate sits at 6.93% for a 60-month new car loan as of March 2026 — the first time it's dropped under 7% since June 2023, according to Bankrate's weekly survey. For used car loans, rates are considerably higher, averaging around 10.5% for qualified borrowers. These are averages for well-qualified applicants. Buyers with lower credit scores or longer terms will see higher rates. Always shop multiple lenders — credit unions and online lenders often beat dealer-arranged financing by 2–4 percentage points.
Financial advisors recommend at least 20% down on a new car and 10% down on a used car. The main reason is depreciation — new cars lose 20–25% of value in the first year, so a 20% down payment helps ensure you're not immediately underwater. According to Edmunds data, drivers put down on average $6,856 for new cars and $4,219 for used cars in the fourth quarter of 2024. The more you put down, the lower your monthly payment, the less interest you pay, and the faster you build positive equity. If you can only afford a small down payment, consider a shorter loan term and/or GAP insurance to protect against being underwater.
The best term is the shortest one you can comfortably afford. A 36-month loan has higher monthly payments but pays the least interest and builds equity fastest. A 48-month loan is widely considered the optimal balance — it satisfies the 20/4/10 rule while keeping payments manageable. A 60-month loan is the most popular in the US and is acceptable if your down payment is strong. Anything beyond 60 months — 72 or 84 months — significantly increases total interest paid and keeps you underwater far longer. On a $30,000 loan at 7%, extending from 48 to 72 months costs an extra $2,800 in interest and leaves you owing more than the car is worth for 3+ additional years.
In general, banks and credit unions offer better rates than dealer financing. Dealers can arrange financing through their network of lenders, but they typically mark up the interest rate and keep the spread as profit — often 1–3 percentage points above what the lender's base rate would be. Credit unions consistently offer the most competitive auto loan rates, particularly for members with good credit. The best strategy is to get pre-approved from your bank or credit union before going to the dealership. You then have a firm rate in hand to compare against the dealer's offer, and you can negotiate from a position of knowledge rather than desperation.
Negative equity — also called being "upside down" or "underwater" — means you owe more on your auto loan than the car is currently worth. For example, if your loan balance is $22,000 but the car's market value is $17,000, you have $5,000 in negative equity. This becomes a problem if you need to sell the car, trade it in, or if it's totaled in an accident. In a trade-in scenario, the dealer will roll that $5,000 into your new loan — meaning you start the new loan already $5,000 underwater. This cycle of rolling negative equity from one loan to the next is one of the most financially destructive patterns in auto financing. The Equity Tracker mode in this calculator shows exactly when your loan balance crosses below the car's value.
In most states, yes — sales tax can be financed as part of the auto loan, which is what most buyers do because it avoids a large upfront cash payment. However, financing the tax means you pay interest on it over the life of the loan, so the real cost is higher than just the tax amount. On a $35,000 vehicle with 7% sales tax, you'd be financing $2,450 in tax — at 7% APR over 60 months, that adds about $460 in extra interest. In five states — Alaska, Delaware, Montana, New Hampshire, and Oregon — there is no sales tax at all. The Standard mode in this calculator lets you choose whether to roll taxes and fees into the loan or pay them upfront.
Auto loan refinancing typically makes sense when: your credit score has improved significantly since you took out the original loan (moving into a better rate tier); interest rates have fallen since your origination date; you financed through the dealership and suspect the rate was marked up; or you need to lower your monthly payment due to a change in financial circumstances. Unlike mortgages, auto loan refinancing usually has no closing costs or fees, which means even a modest rate reduction produces net savings. The Refinance mode in this calculator models the exact monthly savings, total interest change, and break-even point for your specific scenario.
It depends entirely on the specific vehicles and financing being compared — there is no universal answer. New cars carry lower interest rates, manufacturer warranties, the latest safety technology, and sometimes factory rebates or 0% financing promotions. Used cars have a lower purchase price and have already absorbed the steepest depreciation curve. However, used cars carry higher interest rates (averaging 3.7 points above new) and potentially higher maintenance costs. The key is to compare total all-in cost — not just monthly payment. Use the New vs. Used mode in this calculator to enter the exact terms for both vehicles you're considering and see which truly costs less over the loan life.
Beyond the sticker price, common fees include: documentation (doc) fee ($200–$900 depending on state — some states cap it, others do not); title and registration fees ($100–$500 depending on state and vehicle value); destination fee for new cars ($900–$1,500 built into MSRP); dealer advertising fees (sometimes added as a separate line item); and optional add-ons like extended warranties, paint protection, GAP insurance, and tire-and-wheel coverage. Always ask for an itemized "out-the-door" price before agreeing to financing. The calculator above includes doc fees and registration in the loan calculation so you can see their true financed cost. Any fee that cannot be explained clearly is negotiable or should be declined.
This calculator is for educational and planning purposes only and does not constitute financial or insurance advice. Payment calculations use the standard loan amortization formula. Depreciation estimates are based on industry averages and actual depreciation varies by make, model, mileage, and condition. Sales tax rules and rates vary by state and may change. Average rates sourced from Edmunds and Bankrate (March 2026). No personal data is collected or stored. ✦ CatchyTools.com