How Much Car Can You Afford? Budget by Total Monthly Cost

You can afford a car when its whole monthly cost fits in your budget with room to spare, not when a lender approves the payment. Lenders approve loans based on whether you are likely to repay, which is a different question from whether the car leaves you enough for everything else.

So budget in this order: total monthly cost first, then the payment, then the price.

What a car costs each month

The loan payment is usually the largest piece, and it is never the only one.

The Consumer Financial Protection Bureau (CFPB) makes the same point: the vehicle price is not the whole picture, and the interest rate, taxes and fees, optional add-ons, insurance, and ongoing maintenance all affect what you pay.

Insurance deserves a real quote before you choose a car. See car insurance before you buy. For a fuller list of running costs, see total cost of ownership.

The rules of thumb, and what they are worth

You will see a few rules repeated everywhere. They are conventions from personal-finance writing, not regulations or lender requirements. Use them as a first check.

The 20/4/10 rule. Put at least 20% down, finance for no more than 4 years, and keep total car costs at or under 10% of gross income. It is conservative. Many buyers cannot meet all three parts at once, and that does not by itself mean the purchase is a mistake. It is most useful as a warning: if you are far from all three, slow down.

A share of take-home pay. Another common guideline is to keep all car costs within roughly 10% to 15% of take-home pay. Where you fall in that range, or outside it, depends on your rent, debts, and savings goals.

Car price as a share of income. Some people cap the purchase price at a fraction of annual income, often quoted as about a third to a half. This ignores your interest rate and your other costs, so treat it as the roughest of the three.

None of these knows whether you have student loans, cheap rent, or a long commute. Your own budget beats any rule.

Work backwards from your budget

Here is the method in four steps.

1. Pick a total monthly car budget. Look at your take-home pay and existing commitments, and decide what you can spend on a car in total without touching savings goals.
2. Subtract running costs. Insurance, fuel, maintenance set-aside, registration.
3. What is left is your maximum payment.
4. Convert the payment to a price. Payment, rate, and term give you a loan amount. Add your down payment and trade-in equity to get your out-the-door ceiling. Then back out taxes and fees to get the advertised price to shop for.

Worked example

This is an example with round numbers, not typical figures. Substitute your own.

Say your take-home pay is $5,000 a month and you decide $700 is the most you want to spend on a car in total.

Now turn $350 a month into a price. Assume your preapproval is 7% APR.

The out-the-door figure includes tax, title, registration, and dealer fees. If those add around 9% in your area (an assumption for this example; yours will differ), the advertised price to shop for is roughly $17,000 on the 48-month plan or $19,900 on the 60-month plan.

Notice what happened. A person who might be told they "qualify for $35,000" has, by their own budget, a ceiling near $20,000. Both statements can be true. Only one of them is your budget.

You can run your own numbers in the payment calculator and check the tax and fee step with the out-the-door calculator.

The loan-term trap

The fastest way to make an expensive car "fit" is to stretch the loan. It works on the payment and backfires on the total.

Example, $30,000 financed at 7% APR:

The 84-month payment is $265 lower than the 48-month one, and costs about $3,550 more in interest. In practice the gap is often wider, because the FTC notes that longer loans may also carry higher rates.

A long loan also keeps you owing more than the car is worth for longer, which becomes a problem if the car is totaled or you need to sell. See negative equity and APR and loan terms explained.

A fair test: if the car only fits your budget at 72 or 84 months, it is probably the wrong car, not the wrong term.

Down payment and trade-in

A larger down payment lowers the amount you borrow, the interest you pay, and the risk of owing more than the car is worth. The CFPB lists saving for a larger down payment, choosing a less expensive vehicle, and choosing fewer add-ons as the three main ways to bring costs down.

Do not empty your emergency fund to do it. A car with a big down payment and no cushion for a repair is a fragile plan. More in down payment: how much.

Before you set the final number

• Get preapproved. Until a lender gives you a rate, your payment math is a guess. See car loan preapproval.
• Quote insurance on the actual models.
• Leave a margin. If the math says $350, shop as though it said $320. Rates, fees, and insurance rarely surprise you in the cheap direction.
• Keep your ceiling to yourself. If a salesperson asks what payment you want, you can say: "I'm comparing out-the-door prices. I'll sort out the payment once we agree on that." The reason is in dealer sales tactics and how to respond.

If the number is lower than you hoped

That is useful information, and you have options that do not involve a longer loan:

• Look at a lower trim or a smaller model.
• Look at the same model a few years older. See new vs. used vs. CPO.
• Wait a few months and build the down payment.
• Shop your rate at a credit union.

Then search live listings at your real price ceiling and see what is there. People are often pleasantly surprised.