Car Affordability Calculator – How Much Car Can I Afford
Estimate the maximum vehicle price you can afford from a target monthly payment or your income. Enter your loan rate, down payment, trade-in equity, taxes, fees, and monthly driving costs.
Estimate Your Maximum Vehicle Price
Car Affordability Formula
Where:
- \(P\) — maximum vehicle price before sales tax and purchase fees.
- \(L\) — loan amount; \(M\) — monthly loan payment; \(n\) — loan term in months.
- \(r\) — monthly interest rate, equal to Loan APR divided by 1,200 when APR is entered as a percentage.
- \(D\) — cash down payment plus trade-in equity; \(F\) — purchase fees; \(t\) — sales tax rate as a decimal.
- \(G\) — gross monthly income; \(I\) — monthly insurance; \(U\) — monthly fuel; \(O\) — other monthly debt payments.
- \(L_{\text{income}}\) — loan amount supported by \(M_{\text{income}}\) over 48 months.
In Monthly payment mode, the calculator converts your desired payment into a loan amount, then adds your upfront contribution to find the vehicle price. In income mode, it uses the lower of the payment-based price and the price allowed by a 20% down payment. At 0% APR, the loan amount is simply the monthly payment multiplied by the loan term.
Car Affordability – Calculation Example
Example: With the default settings, you want a $400 monthly loan payment for 48 months at 6% APR. You have $6,000 cash down and $2,000 in trade-in equity, with 6% sales tax and $400 in purchase fees.
\[\begin{aligned}r&=6/1200=0.005\\L&=400\frac{1-(1.005)^{-48}}{0.005}\approx\$17{,}032.13\\P&=\frac{17{,}032.1271+6{,}000+2{,}000-400}{1.06}\approx\$23{,}237.86\end{aligned}\]
Result: the maximum vehicle price is $23,237.86 before tax and fees. The loan amount is $17,032.13, and total interest over 48 payments is $2,167.87. With the default $130 insurance and $170 fuel estimates, monthly payment, insurance, and fuel total $700.
How to use the calculator
- Set Calculate by to Monthly payment if you have a target loan payment, or Income and the 20/4/10 rule if you want a price limited by that guideline.
- For Monthly payment mode, enter your Desired monthly payment and Loan term. The available term is 36–84 months. Income mode instead uses a fixed 48-month term.
- Enter Gross monthly income and Other monthly debt payments. Income mode uses both to set a payment limit; Monthly payment mode uses them for the guideline and debt-to-income checks.
- Enter the expected Loan APR, Cash down payment, and Trade-in value. Use only the trade-in equity available toward this purchase, not the vehicle’s full value if you still owe money on it.
- Add the Sales tax rate, Purchase fees, Monthly insurance, and Monthly fuel. Review the maximum vehicle price alongside the loan amount, interest, monthly payment, checklist, and budget details.
What car affordability means here
The Maximum vehicle price is the estimated sticker price you can pay under the selected method—not the full cost of owning the car. Sales tax and purchase fees are added when calculating the amount financed, so they reduce the sticker price your budget can support. Your cash down payment and trade-in equity reduce the loan amount.
The 20/4/10 guideline suggests putting at least 20% of the vehicle price down, financing for no more than four years, and keeping monthly car costs at or below 10% of gross monthly income. This calculator counts the loan payment, insurance, and fuel toward that 10% limit. Income mode enforces all three conditions when finding a price; Monthly payment mode reports whether your chosen payment meets them.
The calculator also checks whether other monthly debt payments plus the car loan payment stay within 36% of gross monthly income. This is an additional debt-to-income check, not part of the 20/4/10 guideline. In income mode, it can set a tighter payment limit than the 10% car-cost rule. In Monthly payment mode, it is a warning rather than a cap on the displayed price.
Assumptions and practical budgeting tips
The estimate assumes a fixed APR and equal monthly payments throughout the loan. Total loan interest is the sum of those payments minus the amount borrowed; it does not include insurance, fuel, or other ownership costs. Your actual APR, taxes, fees, and insurance quote may differ from the amounts entered. Sales tax is applied to the full estimated vehicle price; the calculation does not account for any jurisdiction-specific trade-in tax credit.
Insurance and fuel are useful starting points, but they do not cover maintenance, repairs, parking, registration, or depreciation. Leave room for those expenses and for unexpected bills rather than treating the maximum price as a spending target. You can estimate upkeep timing with the Car Maintenance Due Calculator and refine fuel costs with the Gas Mileage Calculator.
A longer loan term may support a higher vehicle price at the same monthly payment, but it generally increases total interest and may leave you owing more as the car loses value. Compare both the monthly payment and total loan interest before choosing a term. If you are considering leasing instead of buying, use the Car Lease Payment Calculator to examine that different payment structure.
Frequently Asked Questions
How can I check a dealer’s monthly payment quote by hand?
Start with the amount financed: vehicle price plus applicable tax and fees, minus your cash down payment and trade-in equity. For a fixed-rate loan, calculate the monthly payment as \(M=Lr/[1-(1+r)^{-n}]\), where \(L\) is the amount financed, \(r\) is APR divided by 1,200, and \(n\) is the number of months. At 0% APR, divide the amount financed by the number of months. Compare the quote’s loan amount, APR, and term—not just its payment.
Should I enter my annual salary or take-home pay as income?
Enter gross monthly income, before taxes and payroll deductions. If you know your annual gross salary, divide it by 12; for example, $72,000 a year is $6,000 a month. If your income varies, use a conservative monthly average rather than your best month. The guideline uses gross income, but your take-home pay is also worth checking against rent, savings, and everyday expenses before you commit.
What is a good monthly car payment for my budget?
A good payment leaves room for ownership costs and your other financial goals, even if a lender approves more. As a starting check, add the payment to insurance and fuel, then compare that total with your income and actual monthly cash flow. Set aside money for maintenance, registration, and repairs as well. There is no universal “normal” payment: the same amount can be comfortable for one household and risky for another.
What if I owe more on my trade-in than it is worth?
You have negative equity if your loan payoff exceeds the car’s trade-in offer. In that case, there is no positive trade-in equity to enter; use zero rather than the car’s full trade-in value. You would need to pay the shortfall separately or, if a lender permits it, add it to the new loan. Rolling it in increases both the amount borrowed and the risk of owing more than the replacement car is worth.
Why is the out-the-door price higher than the maximum vehicle price?
The maximum vehicle price is a pre-tax, pre-fee price, while the out-the-door price includes charges due at purchase. Ask the seller for an itemized quote so you can compare the vehicle price, tax, registration, documentation charges, and optional add-ons separately. Local tax rules may also change the amount due, particularly when a trade-in qualifies for a tax credit. Check those details before relying on an advertised price.
Does a longer loan term make a more expensive car affordable?
A longer term can lower the payment on a given loan, but it does not reduce the purchase price or borrowing cost. You will generally pay more total interest and may build equity more slowly. Compare offers using the same vehicle price and down payment, then look at both the monthly payment and total amount repaid. A payment that fits only with a very long term may signal that the car strains your budget.