For most families, a car is the second-largest purchase they'll ever make — and the monthly payment is only part of the story. According to NerdWallet, the average monthly payment on a new car loan is now $770, and $531 for used vehicles. Yet many buyers focus almost entirely on "can I afford this month's payment?" without calculating how much of their total paycheck is quietly flowing toward a depreciating asset.

Financial experts recommend keeping your car payment at no more than 10% of your monthly take-home pay — and total vehicle costs (payment, insurance, gas, maintenance) below 20%. On a $3,500 take-home income, that's a maximum payment of roughly $350. But with new car prices averaging over $48,000 in 2025, many buyers are stretching loans to 72 or even 84 months to hit that target — a trade-off that dramatically increases the total interest paid and leaves them "underwater" on the loan for years.

Interest rate and loan term are the two levers you control most. A 1% difference in interest rate on a $22,000 loan over 60 months saves roughly $600. Shortening a 72-month loan to 48 months on the same vehicle can save over $1,000 in interest — even if the monthly payment is higher. The calculator below lets you adjust every variable so you can see exactly where your money is going before you sign anything.