How Much Should You Spend on a Car?
A car is one of the biggest budget-wreckers there is — a depreciating asset many people overspend on. Here's a simple rule to keep it from derailing your finances.
The 20/4/10 rule
- 20% down — put at least 20% down to avoid being "underwater" (owing more than the car is worth).
- 4-year loan max — finance for no more than 4 years. If you can't afford it in 48 months, it's too much car.
- 10% of income — keep total car costs (payment + insurance + gas + maintenance) under 10% of your gross income.
Check a specific car's monthly payment against these limits on the car loan calculator.
Why cars quietly cost so much
The sticker price is only part of it. A new car loses a big chunk of its value the moment you drive off the lot, and then there's insurance, fuel, registration and repairs. Stretching to a 72- or 84-month loan to afford a pricier car means paying more interest and staying underwater for years.
The real cost: opportunity
Spending $15,000 less on a car and investing that difference could grow into a serious sum over time — see what on the compound interest calculator. Buying a reliable, modest car is one of the quietest wealth-building moves there is.
Smart-buying tips
- Consider gently-used — let someone else eat the first year of depreciation.
- Get pre-approved by a bank or credit union before the dealer, so you control the financing.
- Negotiate the total price, not the monthly payment — dealers can lower the payment by stretching the term.
- Don't forget insurance quotes before you buy — they vary a lot by model.
Run the numbers
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Open calculator →Frequently asked questions
What is the 20/4/10 rule?
Put at least 20% down, finance for no more than 4 years, and keep total car costs (payment, insurance, gas, maintenance) under 10% of your gross income.
Should I buy new or used?
A gently used car (two to three years old) usually offers the best value — you skip the steepest depreciation while still getting a reliable vehicle.
Should I take the dealer's financing?
Get pre-approved by a bank or credit union first so you have a benchmark. Sometimes a dealer's promotional rate beats it; often it doesn't, and pre-approval keeps you in control.