Car Cost Calculators & Document Generators

How the calculators work

Every calculator on this page runs entirely in your browser: you enter your own numbers, it does the math instantly, and nothing you type gets stored or sent anywhere. Each one uses the same kind of formula the industry actually relies on for that decision, a standard loan amortization formula for financing (the same approach the CFPB walks through for auto loans), straightforward cost-per-mile math for fuel and EV comparisons, so the result reflects real math instead of a rough rule of thumb. The Auto Repair Invoice Generator and Car Bill of Sale Generator work the same way, entirely client-side, but build a printable document instead of a number.

Which calculator to start with

If you’re deciding whether you can afford a car at all, start with the Car Affordability Calculator, it works from your income and existing bills rather than a specific vehicle price. Once you have a car and a price in mind, the Auto Loan Calculator turns that into an actual monthly payment and total interest figure. Comparing a lease against buying, or a gas car against an EV, points you to the Lease vs Buy Calculator or the Gas vs EV Cost Calculator instead. If you already own a car and are deciding whether to trade it in or sell it privately, the Trade-In vs Sell Calculator lines both paths up side by side.

What you’ll need to enter

Most of these calculators only need a handful of numbers you probably already know: a vehicle price, a down payment or trade-in value, an interest rate, and a loan term for the financing calculators; your typical monthly mileage and a car’s MPG or efficiency rating for the fuel and EV calculators; and your income and monthly debts for the affordability calculator. None of it requires a credit check or contact information, so it’s fine to run a few different scenarios before settling on the real numbers you plan to use.

Nothing you enter is saved once you close the page, so there’s no history to review later and no account to set up first. That also means it’s worth running more than one scenario, a different down payment, a shorter loan term, a used car instead of new, before deciding which numbers to take into a dealership, insurer, or lender.