of a month is for all car costs. After for insurance and running costs, that leaves the payment below.
A longer loan lets the same monthly payment buy a more expensive car. This table shows how much car your payment covers at each term, and what that costs in interest. Your selected term is highlighted.
| Term | Max price | Total interest |
|---|
A common rule of thumb for car buying. As Capital One describes it, you can afford a car if you can:
The rule does not say whether the 10% should be gross or take-home income. Take-home pay is stricter and closer to what you actually have to spend, so enter take-home income if you want the safer answer. It is a guideline, not a law of nature: Capital One's own explainer calls it "only a guideline" and says "it's impossible to make it fit every person's situation." Treat a miss as a warning to look harder at the numbers, not as a ban.
The down payment part has a concrete payoff. The CFPB notes that a larger down payment lowers the amount you need to finance and "may reduce the interest rate charged on the loan."
You earn $75,000 a year and want all car costs under 10% of monthly income. That is $625 a month. Insurance is about $150 and fuel and maintenance another $150, which leaves a $325.00 monthly payment.
With 20% down, a 48-month loan at 7% APR, 6% sales tax and $800 in fees rolled into the loan, that payment supports a loan of $13,572.07 and a car priced up to $14,851. The down payment is $2,970.25 and total interest is $2,027.93.
Stretch the same $325 payment to 72 months and the maximum price rises to $21,236, but interest more than doubles to $4,337.31, and the loan breaks the "4" in 20/4/10. A strict rule gives a modest number. That is the point of it.
You decide $500 a month is your limit, with $3,000 down, 7% APR for 60 months, 6% sales tax and $800 in fees. That payment covers a loan of $25,251.00, so the most you can pay for the car is $25,897, with $4,749.00 in interest.
A salesperson who asks "what payment are you looking for?" can meet $500 a month on a much more expensive car by stretching the term. At 84 months the same $500 covers a car up to $33,329, with $8,871.36 in interest. Decide the price you can afford first, then negotiate the price, not the payment.
The 20/4/10 rule does not specify. Take-home income gives a more conservative and more realistic limit, because it is what your bills are actually paid from.
Everything you pay to keep the car on the road: the loan payment, insurance, fuel or charging, maintenance, and parking or tolls if you pay them regularly. Depreciation is not a monthly bill, so the rule leaves it out.
No. It is the price of the car itself. Taxes and fees are added on top, either financed in the loan or paid at signing, depending on the checkbox. That way you can compare the number directly with a sticker or listing price.
The levers are the same as for any loan: a bigger down payment, a better rate (a pre-approval helps), a trade-in worth more, or a cheaper car. A longer term also works on paper, and the table above shows what it costs.
Results are estimates for informational purposes, not financial advice or a loan offer.