How realistic is the 20/4/10 rule for buying a new car in 2026? – Jalopnik

Life is full of helpful financial reminders, like paying yourself first and maintaining an emergency fund. A guideline that is particularly relevant today, but perhaps less known, is the 20/4/10 rule. It’s a simple calculation: car buyers must make a 20% down payment, not renew financing for more than four years, and not to exceed 10% of their gross income for anything related to the car (monthly payment, insurance, maintenance, gas). The whole point is that you shouldn’t get in over your head when it comes to purchasing a car.

However, as the typical new car costs more than $50,000 each Kelley Blue Book (KBB), and the corresponding monthly loan payment averaging $772, according to Edmundsit’s fair to wonder if the 4/20/10 rule still applies. That 20% of new car loans in 2025 had monthly payments of $1,000 or more makes this sage advice even more questionable.

The answer isn’t that simple and depends on what you buy, how much you make, and how current car prices and ownership costs compare to the line itself. High-income earners who shop conservatively won’t have much trouble following the formula. On the other hand, someone making $63,128 (the average annual salary in the United States) won’t be able to stay within these guidelines if they want an $80,000 car. To determine if the 4/20/10 rule works for mid-market buyers, you’ll need to do some math around fixed costs of ownership, maintenance, and financing.

Let’s explain the rationale behind the 20/4/10 maxim. A typical new car depreciates about 20% in the first year and about 40% after three years AutoEdge. Sure, some vehicles do better or worse, but we’re talking averages. A 20% down payment helps prevent a buyer from sitting upside down on the car (where the loan balance exceeds the value of the vehicle). By the end of 2025, nearly 30% of new car trade-ins were in negative equity, with the underwater amount averaging $7,214, an all-time high according to Edmunds. Rolling over the negative equity from a previous car loan perpetuates the cycle, leading to higher monthly payments and an increased risk of being turned upside down again.

At the same time, a four-year loan is all about keeping the interest a borrower pays to a minimum. In 2025, the average loan for a new car was approximately $42,300 (via Bank rate). At a 6.5% interest rate, financing this amount for four years results in a monthly payment of $1,003 and a total interest expense of more than $5,850, according to KBB. A six-year loan reduces the monthly payment to $711, a decrease of 29%. However, financing costs increase to $8,896. In this situation, the borrower pays an additional $3,046 in exchange for lower monthly payments. Yet loans with a term of seven years are becoming normal.

By keeping total car-related expenses under control (maximum 10% of gross wages), you ensure that there is money left over for housing, food and other essentials. Turn to AAA-provided averages mean total annual costs on the road are $5,747 for insurance ($1,694), fuel ($1,752), registration and taxes ($813), and maintenance, repairs and tires ($1,488). Adding these expenses to the annual sum of monthly payments for a four-year loan ($1,003 multiplied by 12) brings the total to $17,783 per year.

Using the averages above, someone financing a $42,300 car loan would need to earn $177,830 per year to meet the 4/20/10 rule. The challenge is that most Americans (about 88%) earn less than $150,000 a year, according to the US Census Bureau.

Let’s take a different approach by looking at how much car someone can afford (based on the 20/4/10 rule) for more moderate incomes. With an annual salary of $120,000, a car buyer can spend $12,000 each year on all car-related expenses. Subtract the AAA estimated annual expenses of $5,747 for all costs (except financing), leaving $6,253 (or about $521 per month) for loan payments. Using a four-year loan at a 6.5% interest rate results in a loan amount of $22,000 on a $27,500 car (after the 20% down payment and before sales tax and dealer fees). You can choose from five cheap new cars recommended by Consumer Reports or opt for something used.

A new car is not in the picture for someone who earns €75,000 annually. The total car cost of $7,500 or 10% is reduced to $1,753 or $146 per month, after deducting the AAA projected costs. On a four-year loan at 9.65% (used cars often have higher interest rates than new ones), that equates to a financed amount of $5,800 for a $7,250 car, after a 20% down payment. Granted, a used car may be cheaper to insure, but the risk of higher maintenance costs can offset any savings. A lower interest rate can also delay payments. Either way, someone earning closer to the average American salary will have to decide between driving a cheap car, using public transportation, or breaking the 4/20/10 rule.