Car Affordability Calculator
Determine the maximum car price you can afford based on your monthly income, desired payment percentage, down payment, and loan terms. Includes total ownership costs like insurance and fuel.
Car affordability is the most-violated rule in U.S. personal finance. The 20/4/10 rule — 20% down, 4-year loan, total transportation costs (payment + insurance + fuel + maintenance) under 10% of gross income — is the planner's gold standard. The average actual U.S. car loan in 2024 was 68 months on a vehicle that lost value before the loan was halfway paid off, and many households spent 15–20% of gross income on transportation.
This calculator inverts the auto-loan math: given your income and what percentage you're comfortable spending, it tells you the maximum total vehicle price you can buy. It factors in down payment, trade-in, sales tax, the loan term, and ongoing costs (insurance, fuel) so the recommended price reflects what you can actually sustain — not just the loan payment you can technically be approved for.
The result is a ceiling, not a target. Buying right at your maximum leaves no margin for the inevitable surprises: registration, maintenance, an unexpectedly high insurance quote, or a rate that came in worse than expected.
Inputs
Experts recommend 10-15% max
Results
Max Vehicle Price
$26,686
Max Monthly Payment
$500
Total Monthly Ownership
$800
Total Interest
$4,446
Monthly Ownership Costs
Formula
How to use this calculator
- Enter your gross monthly income (pre-tax). Use combined household income if both partners are on the loan.
- Choose what percentage of income you want to allocate to total transportation. 10% is the conservative target; 15% is reasonable for higher earners; 20%+ is the danger zone.
- Enter your planned down payment and any trade-in value.
- Enter the interest rate you've been quoted, your local sales tax rate, and your preferred loan term.
- Estimate monthly insurance (your insurer can give a quote with just a VIN; typical full-coverage averages $1,500–$2,500/year in 2026) and fuel based on your commute and the type of vehicle.
- Review the maximum vehicle price. If it's lower than the cars you've been browsing, you have three options: lower the bar, save more down, or buy used.
Worked examples
Median U.S. income, conservative
Gross monthly income: $5,500 ($66K/yr — close to U.S. median) Allocation: 10% Down payment: $4,000 60-month loan at 6.5%, 7% sales tax Insurance: $150/mo, fuel: $180/mo Max monthly payment: $550 After insurance + fuel: $220 for P&I Max vehicle price: ≈ $15,000 A reliable 2–3 year old used compact or commuter sedan fits this budget. New cars at the same price point are rare.
"Lenders will approve more"
Same income, but allow 20% allocation (close to lender max). Max monthly payment: $1,100 After insurance + fuel: $770 for P&I Max vehicle price: ≈ $43,000 The lender will approve this loan. Affordable doesn't mean wise — 20% of gross to transportation crowds out retirement saving, emergency fund building, and reasonable housing costs. The math works on paper; the financial life rarely does.
When to use this calculator
Use this before walking into a dealership. The single highest-leverage move in car buying is to set your maximum BEFORE you start emotionally attaching to a vehicle. Once you've test-driven a car you love, the cognitive bias is strong — the price you "can afford" tends to creep upward to match what you want.
A few realistic guardrails: - Total transportation: <15% of gross income (10% is comfortable, 20% is stressful) - Loan term: ≤60 months. Beyond that, you'll likely owe more than the car is worth for the first 3+ years - Down payment: ≥20% on a new car or 10% on a used car prevents being upside-down
For the actual loan payment math on a specific vehicle, use the auto loan calculator. For lease-vs-buy comparisons, the lease-vs-buy calculator. For total ownership costs over time, see the car depreciation and fuel cost calculators.
Common mistakes to avoid
- Including only the loan payment in "transportation cost." Insurance, fuel, and maintenance add 50–100% on top of the payment for most owners.
- Stretching the term to make a more expensive car "affordable" on a monthly basis. 72 and 84-month loans bury you in interest and depreciation.
- Forgetting registration and title fees at purchase. These vary by state but commonly run several hundred dollars.
- Not getting an insurance quote before buying. Some cars (sports cars, certain EVs, vehicles popular with thieves) carry much higher premiums than expected.
- Trading in a paid-off car for a "lower payment" on a more expensive vehicle. The math almost always favors keeping the paid-off car.
- Confusing pre-approval with what you can actually sustain. Lenders care about default risk, not your quality of life or other goals.
Frequently Asked Questions
Sources & further reading
- Auto loans — shopping for the best deal — U.S. Consumer Financial Protection Bureau
- Buying a new car — U.S. Federal Trade Commission