NEW YORK–While veteran auto lenders and financial counselors in credit unions are all familiar with the long-standing financial guideline known as the 20-4-10 rule, it has been turned on its ear, according to one new analysis that has found it requires a household income of roughly $120,000 annually to afford the average used vehicle under the rule.
The 20-4-10 rule, which is commonly used by financial planners, recommends buyers put at least 20% down on a vehicle, finance it for no more than four years and keep all vehicle-related expenses — including loan payments, insurance, fuel and maintenance — below 10% of gross income.
But CNBC reported that meeting that standard has become increasingly difficult as used-car prices remain elevated. According to the analysis, the average used vehicle was listed for $26,342 in April, citing data from Cox Automotive.
Using the 20-4-10 formula, CNBC calculated that a buyer purchasing a vehicle at that price would make a down payment of approximately $5,268, leaving $21,074 to finance. Assuming a four-year loan at a 6.98% interest rate, the monthly payment would be about $505.
Related Expenses on the Rise
The analysis found that ownership costs extend well beyond the loan payment. CNBC estimated average monthly expenses of about $190 for insurance, $201 for fuel and roughly $100 for maintenance and repairs. Combined with the loan payment, total vehicle costs approach $996 per month, or nearly $12,000 annually.
Under the 20-4-10 rule, CNBC reported, a household would need gross annual income of about $120,000 to keep transportation costs within the recommended limit.
That income threshold is well above what many Americans earn. CNBC noted that the median U.S. household income was $83,730 in 2024, citing data from the U.S. Census Bureau.
Financial planners interviewed by CNBC said they continue to endorse the guideline despite its growing difficulty to achieve, arguing that the rule serves as an important safeguard against overspending on vehicles.
‘Wealth Killers’
“Cars have quietly become one of the biggest wealth killers in the middle-class budget,” Mark Stancato, a certified financial planner with VIP Wealth Advisors, told CNBC.
