Car Affordability Calculator
Work backwards from a comfortable monthly payment, or from your take-home pay, to the car price you can actually afford. Factor in your down payment, trade-in, rebates, sales tax, and fees, and see the sticker price, the out-the-door total, the loan, and the interest it all implies.
Formula
Worked example
A 400/mo budget at 7% APR over 60 months supports a loan of about 20,201 (i = 0.07/12). Add 3,000 down for a 23,201 out-the-door budget. With 500 in fees and 7% tax, the sticker you can afford is (23,201 - 500) / 1.07 rounded to about 21,216, with roughly 1,485 of that going to sales tax.
Working backwards from a payment or your income
Most car shoppers know what they can pay each month long before they know what sticker price that buys. This calculator runs amortization in reverse: it takes your monthly payment, the loan monthly interest rate, and the number of months, then solves for the largest loan those payments can repay. If you would rather start from your paycheck, switch the mode to take-home pay and the tool sets the payment for you using a share of net income, with 10% a common ceiling. Either way, you get the loan a budget supports without guessing.
From a loan to a real out-the-door price
The loan is only part of the deal. Your cash down payment, the equity in a trade-in, and any rebates all add to what you can spend, so the calculator sums them with the loan to get an out-the-door budget. That total has to cover the vehicle plus sales tax plus flat fees, so the tool backs the sticker price out of it: it subtracts the fees, then divides by one plus the tax rate. The result is the actual sticker price you can shop for, with the sales tax and fees shown separately so nothing sneaks up on you at signing.
Why the rate, term, and cash all move the answer
A longer term spreads the same payment over more months, so it supports a bigger loan and a pricier car, but you pay far more interest and stay underwater longer. A higher APR shrinks the loan a given payment can carry. A bigger down payment or trade-in raises the price you can reach without raising the payment at all, and lowers the interest you pay. Lowering the rate, shortening the term, and putting more cash down are the levers that change what you can afford and how much it truly costs.
Remember the costs the loan ignores
The sticker this tool returns covers only the vehicle; tax and fees are broken out, but insurance, maintenance, and fuel are extra and can add thousands per year. A common guideline, sometimes called the 20/4/10 rule, is to put at least 20% down, finance for no more than four years, and keep total transportation spending, payment plus insurance and fuel, under about 10 to 20% of take-home pay. These figures are planning estimates, not a loan offer; your actual rate and approval depend on credit, lender, and the vehicle.
Affordability guidelines and typical inputs
| Guideline | Target | Why it matters |
|---|---|---|
| Monthly payment | <= 10% of take-home pay | Keeps the payment comfortable month to month |
| Total transport cost | <= 15 to 20% of take-home | Includes insurance, fuel, and upkeep |
| Down payment | >= 20% (new), 10% (used) | Reduces interest and avoids being underwater |
| Loan term | <= 48 months (4 years) | Longer terms cost much more interest |
| Sales tax | ~5 to 9% (US, varies) | Added to the price; not part of the sticker |
Rules of thumb lenders and consumer groups often cite; adjust to your own situation.
Frequently asked questions
How much car can I afford on a $400 monthly payment?
At 7% APR over 60 months, a $400 payment supports roughly a $20,200 loan. With $3,000 down that is about a $23,200 out-the-door budget, which at 7% sales tax and $500 in fees works out to a sticker price near $21,200. A longer term or lower rate raises that figure; a higher rate lowers it.
How much should my car payment be based on my income?
Switch the calculator to take-home pay mode and it applies a percentage of your net monthly income, defaulting to 10%, which many lenders and consumer groups treat as a comfortable ceiling. Total transportation spending, including insurance and fuel, is usually kept under about 15 to 20% of take-home pay.
Does this include sales tax, fees, and my trade-in?
Yes. The calculator adds your down payment, trade-in equity, and rebates to the loan to get an out-the-door budget, then backs the sticker price out by removing flat fees and the sales tax. It shows the sticker price, the out-the-door total, the tax, and the fees separately so you can shop with the right number.
Is a longer loan term a good way to afford more car?
It lets a given payment buy a pricier car, but you pay much more interest overall and risk owing more than the car is worth for years. Shorter terms with a solid down payment or trade-in are cheaper in the long run, which is why the 20/4/10 rule caps the term at four years.