Where the percentages come from
The ceiling used here is the same one our buying guides use: every car cost together stays inside 15 to 20 percent of take-home pay, with 15 as the conservative end. Take-home rather than gross, because gross never reaches your account.
The 48-month default term comes from the classic 20/4/10 rule: 20 percent down, four years maximum, and all transport costs under 10 percent of gross pay. The rule has not stopped working; it has become harder to meet, which is a signal about car prices rather than permission to ignore it. The full reasoning behind both is in how much car can I afford.
Read the result as a ceiling, not a target
The headline figure is the vehicle price your budget supports, and it is a maximum. Buying at it leaves no room for the repair that arrives in year three.
What each output means
- All-in monthly car budget
- Everything the car may cost you each month
- Left for the payment
- What remains once insurance, fuel and upkeep are paid
- Loan that payment supports
- The balance that payment amortizes over your term
- Vehicle price you can carry
- That loan plus your cash up front, before tax and fees
The price shown sits before sales tax and fees, because those are financed on top. On a 6 percent tax rate plus $800 in fees, the sticker you should actually shop is roughly 6 to 8 percent below the number here.
What changes the answer most
Running costs move the result more than buyers expect. Every $50 a month of insurance is around $2,000 of car at a typical rate and term, so a cheap-to-insure model raises the car you can afford without raising your income.
The term is the second lever, and it is the dishonest one.
Stretching from 48 to 72 months raises the price this tool reports, but it leaves you paying more interest and staying underwater longer.
If the car only fits at 72 months, it does not fit.
Turn the ceiling into a shortlist
Once you have a price ceiling, shop against it rather than against a monthly payment. Our model profiles carry a price range and an ownership-cost section for every car, so you can check both halves of the budget before a test drive.
When you have a specific car and a quoted rate, run the exact deal through the car payment calculator to see the payment, the amount financed, and the interest total for that car rather than for a budget in the abstract.