🚗 Car Affordability Calculator
Enter your monthly take-home income, existing debt payments, down payment, loan term, and interest rate to see the maximum monthly car payment and car price a standard debt-to-income guideline suggests - free and unlimited, no sign-in required.
Your numbers
By default this uses a 15% guideline - your total monthly car payment plus existing debt payments should not exceed 15% of your take-home pay. You can adjust that percentage below.
Suggested affordability
This is a suggested ceiling, not a preapproval - actual loan offers depend on your credit, the lender, and the vehicle. Property tax, insurance, and maintenance costs are not included.
How the ceiling is worked out
A debt-to-income guideline caps the monthly payment, which is then turned back into a loan balance by the standard amortisation formula run in reverse, solved for principal.
payment = income × (guideline / 100) - existing debt (floored at 0)
i = (rate / 100) / 12 n = years × 12
loan = payment × (1 - (1 + i)^-n) / i (at 0%: loan = payment × n)
price = loan + down paymentTake the placeholder figures: $5,000 take-home, $300 of existing debt payments, the default 15% guideline, 6.5% over 5 years, $3,000 down. The payment ceiling is 5,000 × 0.15 - 300 = $450. At i = 0.00541667 over 60 months the annuity factor is 51.10868, so the loan is $22,998.91 and the car price $25,998.91.
What each box wants
Take-home income is what lands in your account after tax and deductions, not salary. Existing debt payments are your other non-mortgage minimums: card, student loan, a car you still owe on. Leave the guideline empty and 15% is applied.
- Guideline % — 1 to 50. Fifteen is the cautious end of the usual 15-20% rule.
- Rate — the APR your credit score would actually be quoted.
- Term — 1 to 10 years. A longer term buys a dearer car at the same payment, at much more interest.
Frequently asked questions
What percentage of income should go on a car payment?
Fifteen percent of take-home pay, covering every non-mortgage debt payment you already have. The commonly quoted range runs to 20%; past that a car starts crowding out everything else.
Why does it say I can afford nothing?
Your existing debt payments already reach the guideline on their own. At $5,000 income and 15%, $750 or more of current payments leaves no room, and the result is floored at zero rather than turning negative.
Does a bigger down payment raise the car price I can afford?
Yes, dollar for dollar — it is added onto the loan your payment supports. It does not lift the monthly payment ceiling, which depends only on income and existing debt.