The 15% and 20% rules
Two widely used guidelines for car affordability: the 15% rule says your total car costs (payment + insurance + fuel + maintenance) shouldn't exceed 15% of your monthly take-home pay. The stricter 20/4/10 rule says: 20% down, loan no longer than 4 years, and total car costs under 10% of gross income.
Why total cost of ownership matters more than the monthly payment
Dealers focus on monthly payment because it sounds small. But insurance, fuel, and maintenance can easily add $400–700/month on top of the loan payment. This calculator shows you the full picture.
Frequently asked questions
New vs used — which is more affordable?
Used cars typically cost less upfront and have lower insurance premiums, but may have higher maintenance costs. New cars often come with warranties and better financing rates. Run both scenarios in this calculator to compare.
Is my data saved?
No. Everything runs locally in your browser.
For educational purposes only; not financial advice. Insurance and maintenance estimates vary widely. Get real quotes before making a purchase.