Car Affordability CalculatorHow Much Car Can I Afford? (20/4/10 Rule)
The 20/4/10 rule says: put at least 20% down, finance for no more than 4 years, and keep total car costs — payment, insurance and fuel — under 10% of gross income.
Find a realistic car price for your income. Based on the popular 20/4/10 rule, it counts insurance and fuel — not just the payment — then works backward through your loan rate, term, down payment, trade-in and sales tax to a maximum sticker price.
Your budget
20/4/10 rule: 10% of gross income for payment, insurance and fuel. Some planners allow up to 15%.
Out-the-door about $16,728 with tax. Based on a $625 monthly car budget (10.0% of income).
Fits the 20/4/10 ruleMonthly car budget
Same payment, different terms
| Loan term | Max car price | Total interest |
|---|---|---|
| 36 months | $12,239 | $1,174 |
| 48 months | $15,781 | $2,028 |
| 60 months | $19,085 | $3,087 |
| 72 months | $22,166 | $4,337 |
| 84 months | $25,039 | $5,766 |
How much car can I afford?
The 20/4/10 rule says: put at least 20% down, finance for no more than 4 years, and keep total car costs — payment, insurance and fuel — under 10% of gross income. On a $75,000 salary that’s $625 a month. After $150 insurance and $150 fuel, a $325 payment at 7% APR over 48 months supports a car of about $15,781 with 20% down and 6% sales tax.
Part of our Car Buying & Ownership calculators — for the core estimate, start with the Cost of Car Ownership Calculator.
The 20/4/10 car buying rule explained
20% down
A 20% down payment keeps your loan smaller than the car’s value from day one, protecting you from negative equity as it depreciates.
4-year loan
Financing for 48 months or less limits total interest and means the car is paid off while it still has meaningful value.
10% of income
Keeping payment, insurance and fuel under 10% of gross income leaves room for savings and other goals. Some planners stretch this to 15% for people with no other debt.
How to use the car affordability calculator
Enter your income
Use gross (pre-tax) household income.
Add running costs
Get an insurance quote and estimate monthly fuel.
Set the loan
Use the APR you’re pre-approved for and your preferred term.
Add down payment, trade-in and tax
The calculator works back to a maximum sticker price.
How the maximum car price is calculated
Affordable payment = budget − insurance − fuel
Loan amount = payment × [1 − (1 + r)^−n] ÷ r (r = APR ÷ 12, n = months)
Max price = (loan amount + trade-in) ÷ (1 + sales tax − down payment %)
Worked example (the calculator’s defaults): $75,000 ÷ 12 × 10% = $625. $625 − $150 − $150 = $325 payment. At 7% over 48 months that finances $13,572. Dividing by (1 + 0.06 − 0.20) gives a maximum price of about $15,781 with $3,156 down.
Once you have a target price, add your state’s tax with the Car Sales Tax Calculator to get the real out-the-door figure.
How much car can I afford on my salary?
| Gross income | 10% monthly budget | Max price* | 15% monthly budget | Max price* |
|---|---|---|---|---|
| $40,000 | $333 | $1,619 | $500 | $9,712 |
| $50,000 | $417 | $5,665 | $625 | $15,781 |
| $60,000 | $500 | $9,712 | $750 | $21,851 |
| $75,000 | $625 | $15,781 | $938 | $30,956 |
| $100,000 | $833 | $25,898 | $1,250 | $46,130 |
| $125,000 | $1,042 | $36,014 | $1,562 | $61,305 |
| $150,000 | $1,250 | $46,130 | $1,875 | $76,479 |
*Assumes $300 a month for insurance and fuel, 7% APR, 48 months, 20% down, 6% sales tax and no trade-in.
Tips before you shop
- Get pre-approved with a bank or credit union so you know your real rate before the dealer’s finance office.
- Negotiate the out-the-door price, not the monthly payment.
- Get an insurance quote on the exact model first.
- Avoid rolling negative equity from a trade-in into a new loan.
- Keep an emergency fund rather than putting every dollar down.
Then run the exact loan through our Auto Loan Calculator and check the long-term cost with the Cost of Car Ownership Calculator.
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Car Affordability Calculator FAQs
Using the 20/4/10 rule, total car costs should stay under 10% of gross income. On $75,000 that’s $625 a month for payment, insurance and fuel, which supports roughly a $15,000–$16,000 car at 7% APR over four years with 20% down.
Put at least 20% down, finance for no more than 4 years, and keep monthly payment, insurance and fuel under 10% of gross monthly income.
Many people find it conservative, especially with today’s prices. Some planners allow up to 15% of income. The stricter rule leaves more room for savings and emergencies.
A common guideline is that the payment alone shouldn’t exceed about 10% of take-home pay, and total car costs shouldn’t exceed 10–15% of gross income.
Longer loans lower the payment but increase total interest and the risk of owing more than the car is worth. Shorter terms are usually safer.
Aim for 20% on a new car and at least 10% on a used car to reduce interest and avoid negative equity.
Yes. Enter your rate and the maximum price is reduced so the price plus tax fits your loan and down payment.
Yes. A pre-approval from a bank or credit union tells you your real rate and budget, gives you a benchmark to compare with dealer financing, and keeps the negotiation focused on the car’s price.
About the developer
Manzoor Ahmad
Web Designer & Calculator Developer · 13+ years of web development and SEO experienceI’m a professional pharmacist turned tech geek, and I designed and coded this car affordability calculator myself. The 20/4/10 rule is a guideline, not a law, so the tool lets you change every part of it and shows the looser 15% version alongside.
Found a number that looks wrong, or want a feature added? Tell me through my author page — corrections are fixed and re-dated.
Sources
- Consumer Financial Protection Bureau — Auto loans: key terms and shopping tips
- Federal Trade Commission — Buying a new car
- Federal Reserve — Consumer credit (G.19): auto loan rates
Disclaimer: This is an educational estimate, not financial advice or a loan offer. Your actual rate, taxes, fees and insurance depend on your credit, location and lender.
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