Start With the Monthly Number, Not the Sticker
Dealers like to ask "what payment are you looking for?" because almost any car can hit almost any payment if the loan is long enough. Flip the question. Decide what you can spend on transportation each month, then work backwards to a price, and only then go shopping.
The Consumer Financial Protection Bureau recommends deciding what you can afford and getting preapproved before you visit a dealer, so you know your rate and can compare the dealer's financing offer against it.
Step 1: Set a Total Monthly Car Budget
A widely used rule of thumb is to keep total car costs (loan payment, insurance and fuel) at or below about 10% of gross monthly income. Some planners allow up to 15% for people with no other debt. On a $60,000 salary, 10% is $500 a month.
Then subtract the costs that come with any car:
- Insurance: get real quotes for the models you're considering. Premiums vary a lot by driver, ZIP code and vehicle.
- Fuel or charging: estimate your miles per month ÷ the car's MPG × the local fuel price. Our gas mileage guide shows how.
- Maintenance and repairs: set aside something every month even for a new car, since tires and brakes wear out on schedule.
What's left is your maximum loan payment. If $500 total leaves $150 for insurance and gas, you have $350 a month for the payment.
Step 2: Turn the Payment Into a Price
The amount a payment can buy depends on the APR and the term. Here is what $350, $500 and $650 a month will finance at 7% APR:
| Monthly payment | 48 months | 60 months | 72 months |
|---|---|---|---|
| $350 | $14,616 | $17,676 | $20,529 |
| $500 | $20,880 | $25,251 | $29,327 |
| $650 | $27,144 | $32,826 | $38,125 |
Add your down payment and trade-in equity to the amount financed, then subtract taxes and fees, and you have the sticker price you can shop for.
The 20/4/10 Rule of Thumb
A popular shortcut combines three limits:
- 20% down so you are less likely to owe more than the car is worth as it depreciates.
- 4-year (48-month) maximum term to limit interest and get to a paid-off car sooner.
- 10% of gross income for all car costs.
It's conservative, and many buyers won't hit every part. But each piece points at a real risk: little equity, long loans and a budget squeezed by a car.
Why Loan Term Matters So Much
Stretching a loan makes a car look cheaper by the month while making it more expensive overall. On $30,000 at 7% APR:
| Term | Payment | Total interest |
|---|---|---|
| 48 months | $718.39 | $4,483 |
| 60 months | $594.04 | $5,642 |
| 72 months | $511.47 | $6,826 |
| 84 months | $452.78 | $8,034 |
Going from 60 to 84 months lowers the payment by about $141 but adds about $2,400 of interest. Long terms also keep you "underwater" longer, which hurts if the car is totaled or you want to trade it in early. The FTC advises looking at the total cost of the loan, not just the monthly payment.
Don't Forget Taxes, Fees and the Trade-In
Your budget is the out-the-door price: the negotiated price plus sales tax, title, registration and dealer fees. Sales tax alone can be large. State rates run from 0% in a few states to 7.25% in California, before local taxes (Tax Foundation, midyear 2026).
Most states tax only the difference between the new car's price and your trade-in's value, which can save hundreds of dollars. If you still owe money on the trade-in, the payoff is subtracted from its value; if you owe more than it's worth, that negative equity gets rolled into your new loan and makes it bigger.
Worked example
- Price: $35,000, with $4,000 down and an $8,000 trade-in on which you owe $3,000.
- Sales tax: at 7% on the price minus the trade-in ($27,000), tax is $1,890. Fees are $700.
- Amount financed: $35,000 + $1,890 + $700 − $4,000 − ($8,000 − $3,000) = $28,590.
- Payment: at 7.5% APR for 60 months, about $572.88 a month, with about $5,783 of interest over the loan.
In a state that taxes the full price, tax would be $2,450 and the payment about $584.11. Try your own numbers in the auto loan calculator.
Your APR Changes Everything
Your credit score has a big effect on the rate you're offered, and the rate has a big effect on what you can afford. Before shopping:
- Check your credit report for errors (free at AnnualCreditReport.com).
- Get preapproved by a bank or credit union so you have a rate to beat.
- Compare APRs, not just payments, and for the same term. Our guide to how APR works explains why.
- Look at add-ons separately. Extended warranties, GAP coverage and service contracts are optional and can be bought or declined on their own. Don't let them be folded into a payment quote without seeing their price.
New, Used or Lease?
A used car usually lets the first owner absorb the steepest depreciation, though used-car loan rates are often higher. A lease can have a lower payment, but you don't own the car at the end, and mileage limits and wear charges apply. For most buyers who keep cars for many years, buying a reliable car and driving it well past the payoff date is the cheapest way to own one.
A Quick Checklist
- Pick a monthly car budget, usually 10–15% of gross income.
- Subtract insurance, fuel and maintenance to get the payment.
- Get preapproved and know your APR.
- Choose the shortest term you can manage.
- Convert the payment to a price, add your down payment and trade-in equity, and subtract tax and fees.
- Negotiate the out-the-door price, not the payment.
Budget for the Whole Time You Own It
The payment ends; the car's costs don't. Registration renews every year, tires and brakes wear out, and repairs become more likely once the warranty ends. When you compare two cars, estimate the total over the years you expect to keep each one: payments, insurance, fuel, maintenance and expected resale value. A slightly more expensive car that holds its value and uses less fuel can cost less overall than a cheaper one.
Frequently Asked Questions
What is the 20/4/10 rule for buying a car?
A rule of thumb: put at least 20% down, finance for no more than 4 years, and keep total car costs (payment, insurance, fuel) under about 10% of gross income. It is a guideline, not a lender requirement.
How much car can I afford on a $60,000 salary?
Using 10% of gross income ($500 a month) for all car costs, and leaving about $150 for insurance and fuel, about $350 is left for a payment. At 7% APR over 48 months that supports roughly $14,600 financed, plus your down payment.
Is a 72- or 84-month car loan a bad idea?
It lowers the payment but raises total interest and makes it more likely you will owe more than the car is worth for years. Use one only if you understand the extra cost.
Should I include sales tax in my car budget?
Yes. Tax, title, registration and dealer fees can add several thousand dollars. Your budget should be the out-the-door price, not the sticker price.
Sources
- Consumer Financial Protection Bureau, "Auto loans" resources and "Buying a car" guidance (consumerfinance.gov/consumer-tools/auto-loans).
- Federal Trade Commission, "Understanding Vehicle Financing" (consumer.ftc.gov).
- Tax Foundation, State and Local Sales Tax Rates, Midyear 2026 (taxfoundation.org).
This guide is for education. Figures are current as of October 2026; for tax, lending or legal decisions, check the rules that apply to you.