Car Affordability Calculator
Car affordability is determined by your income, existing debt, down payment, and loan term — calculated here using the 20/4/10 rule: 20% down, a 4-year (48-month) max loan term, and total transportation costs under 10% of gross monthly income. This calculator applies the same conservative guideline financial planners use to keep a car purchase from straining your budget.
How Car Affordability Is Calculated
The 20/4/10 rule is a conservative benchmark — well inside what most lenders will actually approve — designed to prevent the two most common car-buying financial traps: being upside-down on the loan and letting transportation costs crowd out savings.
20%
Minimum down payment of the purchase price
4 Years
Maximum loan term (48 months)
10%
Max transportation cost ÷ gross monthly income
| Term | Definition |
|---|---|
| Transportation Cost | Loan payment + insurance premium (excludes fuel and maintenance) |
| LTV | Loan-to-value — the loan amount divided by the vehicle's price |
| Financed Tax | State sales tax rolled into the loan amount rather than paid upfront |
Example: On $75,000/year income ($6,250/month gross), the 10% transportation ceiling is $625/month. After subtracting a $150/month insurance estimate, roughly $475/month remains for principal and interest — which, amortized over 48 months at a typical rate, supports a maximum vehicle price in the low-$20,000s once sales tax and down payment are factored in.
⚠️ Expert Pro-Tip
Dealers will approve you for far more than the 20/4/10 rule recommends. Auto lenders routinely stretch loans to 72 or even 84 months specifically to fit a higher price into a payment that looks affordable — but longer terms mean you pay more total interest and stay "upside-down" (owing more than the car is worth) for years, which is dangerous if you need to sell or trade in early. Stick to the 48-month cap even if a longer term is offered, and treat the "stretch" result here as a hard ceiling, not a target.
Car Affordability Calculator
Your Financial Profile
Ownership Costs
Affordability Results
Recommended Max Car Price
$22,098
Based on the 20/4/10 rule
If Stretching Your Budget
$34,177
Using 15% of gross income (higher risk)
Monthly Payment Breakdown
| Loan Payment | $475.00 |
| Insurance | $150.00 |
| Total Monthly Transportation Cost | $625.00 |
Rule Checks
Transportation-to-Income
Payment + insurance ÷ gross income (max 10%)
Total Debt-to-Income
All debts + transportation ÷ gross income (max 36%)
Down Payment
⚠ Below the recommended 20%
Based on your results — what to do next:
Get your exact loan payment
You can afford up to $22,098. Plug in a specific vehicle price to see the exact payment and full amortization schedule.
Compare buying vs. leasing
See if leasing a similarly priced vehicle lowers your monthly cost below $475.00.
See the net worth impact
A car is a depreciating asset. Track how a $22,098 purchase with $4,000 down affects your overall net worth.