Car Affordability Calculator
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Planning estimate only — not financial or tax advice. Consult a qualified professional for personal decisions. 20/4/10 rule — 20% down, 4-year loan, total car costs ≤ 10% of monthly income.
Rates last reviewed: July 2026
Income & loan rate
Max vehicle price
$21,924.11
$420.00/mo loan · $4,384.82 down (20%)
- Max loan amount
- $17,539.28
- Total car budget (10%)
- $600.00
- Loan term
- 48 months
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The 20/4/10 car rule
The 20/4/10 rule is a conservative budgeting framework: put 20% down, finance for no more than 4 years (48 months), and keep total monthly car costs — payment, insurance, fuel — at or below 10% of gross income.
This calculator estimates a maximum loan payment by reserving roughly 3% of income for insurance and fuel, then backs into loan amount and vehicle price at your interest rate. Actual insurance and fuel vary by vehicle, location, and driving history.
Example: $6,000/month income → $600/month total car budget. After ~$180 for insurance/fuel estimate, about $420 remains for the loan payment → roughly a $17,000–$18,000 loan and ~$21,000–$22,000 vehicle price at 7% APR with 20% down.
Official sources
Rates and formulas in this calculator reference the documentation below. Confirm current numbers on the source site before relying on them. Links do not imply endorsement by those organizations of Calcometry or this tool.
Common questions
What counts toward the 10%?
Payment, insurance, fuel, maintenance, and registration. This tool estimates insurance/fuel at 3% of income — adjust your real budget if yours differs.
Can I stretch beyond 4 years?
Longer terms lower payments but increase interest and upside-down risk. The 20/4/10 rule intentionally limits term length.
Is this a loan approval estimate?
No. Lenders use credit score, debt-to-income, and their own policies. Use this as a personal affordability cap, not a pre-approval.