Car Affordability Calculator

How much car can you actually afford based on your income and budget?

Last updated April 2026
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Based on the 10% rule
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20/4/10 Rule Check
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Disclaimer: This calculator is for general educational and informational purposes only. It does not constitute financial advice, investment advice, tax advice, or legal advice and is not a substitute for consultation with a qualified professional. No fiduciary or advisory relationship is created by your use of this tool. Results are estimates based on the inputs you provide, standard mathematical formulas, and publicly available data that may not be current and may not reflect your individual financial situation, applicable tax laws, or other relevant factors. Neither MayoCalc nor Cook Media Systems assumes any liability for losses, damages, or other consequences arising from the use of any information or results provided by this tool. Always consult a qualified financial advisor, certified public accountant, or attorney before making financial decisions. See our full Disclaimer and Terms of Service.

How Much Car Can You Afford?

The most widely recommended guideline is the 20/4/10 rule: put at least 20% down, finance for no more than 4 years (48 months), and keep total transportation costs (payment + insurance + gas + maintenance) under 10% of your gross monthly income.

Max Monthly Payment = (Gross Monthly Income x 10%) - Insurance - Gas
Max Loan = Payment x [(1-(1+r)^-n) / r]
Max Car Price = Max Loan + Down Payment + Trade-In

Why the 20/4/10 Rule Works

A 20% down payment prevents you from going "upside down" (owing more than the car is worth) since new cars depreciate about 20% in the first year. A 4-year maximum term limits total interest and ensures you build equity faster than the car depreciates. The 10% income cap ensures transportation costs do not crowd out savings, housing, and other priorities.

Common Mistakes

Focusing on the monthly payment instead of total cost. A $400/month payment sounds affordable, but over 72 months at 8%, you pay $28,800 for a $22,000 car. Ignoring insurance costs (a new BMW costs 3-4x more to insure than a Honda Civic). Not accounting for maintenance ($500-1,000/year for most cars, $2,000+ for luxury brands). Stretching to a 72 or 84-month loan just to afford a more expensive car.

The True Cost of Car Ownership

The purchase price is only the beginning of car costs. AAA estimates the average annual cost of owning a new vehicle at approximately $12,000 to $13,000 when including depreciation, fuel, insurance, maintenance, registration, taxes, and financing charges. Depreciation is the largest single cost, averaging $4,000 to $5,000 per year for a new car in the first five years (with the steepest drop in year one at 20 to 25%). The rule of thumb for affordability is the 20/4/10 rule: 20% down payment, 4-year maximum loan term, and total transportation costs (payment, insurance, fuel, maintenance) under 10% of gross monthly income. Buying a 2 to 3 year old certified pre-owned vehicle can save 30 to 40% compared to buying new while retaining manufacturer warranty coverage.