Couple driving in their convertible through the San Francisco bridge
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Hey you, sizing up that super-sleek sports car that would make you the envy of Instagram.

Better ask yourself: Can you really afford it? Honestly?

Bankrate finds buying a car can be a serious financial challenge around the U.S., and you might easily spend more than you should.

Our latest Car Affordability Study shows typical households in most of America’s larger cities don’t earn enough to afford the average new vehicle, under a common budgeting rule for buyers. You may need to stay away from those pricey cars in the showroom and focus on the less expensive models at the back of the lot.

10 most affordable cities to buy a car

What’s ‘affordable’?

The “20/4/10” rule says you should aim to put down at least 20 percent of a vehicle’s purchase price, take out a car loan for no longer than four years, and devote no more than 10 percent of your annual income to car payments, interest and insurance.

If you can’t stay within those lines, you can’t afford the car.

With the 20/4/10 rule in mind, Bankrate reviewed incomes and vehicle costs in the 25 largest metro areas, and considered that the average price for a new car or light truck sold in the U.S. during May was about $33,300, according to Kelly Blue Book.

We used insurance data from The Zebra, local sales tax data from TaxJar, and data on population and household incomes from the census to calculate each city’s affordable price after taxes and insurance costs.

What we’ve found is the average new vehicle can be considered truly affordable only in the Washington, D.C., area, though San Francisco isn’t far behind.

New car affordability, city by city
Rank Metro area Affordable price (before taxes) Margin between affordable price and average price
1 Washington, D.C. $37,223.41 11.91%
2 San Francisco $32,286.08 -2.93%
3 Boston $30,863.38 -7.21%
4 Seattle $26,771.36 -19.51%
5 Minneapolis-St. Paul $26,605.71 -20.01%
6 Baltimore $26,355.39 -20.76%
7 Denver $24,485.39 -26.38%
8 San Diego $23,439.74 -29.53%
9 Chicago $23,386.08 -29.69%
10 Portland, Oregon $23,208.91 -30.22%
11 Philadelphia $22,600.28 -32.05%
12 New York $22,380.46 -32.71%
13 Atlanta $21,641.72 -34.93%
14 Charlotte, North Carolina $20,553.31 -38.21%
15 Los Angeles $19,879.44 -40.23%
16 St. Louis $19,840.30 -40.35%
17 Phoenix $19,570.73 -41.16%
18 Dallas $19,038.21 -42.76%
19 Houston $18,857.72 -43.30%
20 Riverside-San Bernardino, California $17,832.99 -46.38%
21 San Antonio $16,432.50 -50.60%
22 Orlando, Florida $15,902.47 -52.19%
23 Tampa-St. Petersburg, Florida $14,189.35 -57.34%
24 Detroit $13,912.50 -58.17%
25 Miami $13,576.83 -59.18%

Local costs can be high

In Miami, the metro area worst for affordability, a typical household can afford to pay only about $13,600 without breaking the 20/4/10 rule.

Brooke Waszak, a real estate agent in Lake Worth, Florida, is well-acquainted with the high cost of car ownership in the region that includes Miami. She recently traded in a very old vehicle for a late-model used car and was blindsided by a more than 100 percent increase in her car insurance premiums.

Having to make sales calls that often involve driving, she doesn’t regret the purchase but wishes she had taken into account the various taxes and fees and higher insurance costs when making her decision.

“I didn’t factor it in at all,” Waszak says.

A national issue

While the various costs of owning a car can vary from place to place, auto affordability is an issue nationwide.

Even today’s average used-car price of around $19,200 would be hard for households in eight of the 25 biggest metro markets.

“In the past 35 years, the cost of a new car has gone up 35 percent, a used car is up 25 percent, and at the same time, the median household income is only up 3 percent,” says Michelle Krebs, a senior analyst for Autotrader.

One way consumers are bridging the affordability gap is with longer-term car loans. These days, three quarters of new-car loans are written for longer than five years, and growing numbers of loans have terms as long eight years, according to Experian.

Play by the rules

The length of an auto loan may not seem important, especially with today’s more reliable autos routinely going well beyond 100,000 miles without major issues. But playing by the 20/4/10 rule can make a big difference in your long-term financial well-being.

When people commit to bigger car purchases than they can afford, “at some point, something has to give, so either they end up falling behind in some other area, or they end up falling behind … on their vehicle payment,” says Dylan Ross, a Certified Financial Planner professional and director of financial planning at the Garrett Planning Network.

His advice is to buy a car affordable enough to give you room in your budget to save for its replacement.

Even if you can’t save enough to pay cash for your next car, you’ll be able to put more money down and ease yourself off the car debt treadmill.