Car Affordability Flow
Find the safe car price using the 10/15/36 rule from your real take-home pay and existing debts.
Get a safe monthly car payment and maximum car price.
Why this flow matters
Cars are the largest depreciating asset most people buy, and dealers are trained to anchor on monthly payment so longer terms feel cheaper. This flow inverts that game: it derives the safe car price from rules grounded in your take-home pay, then shows you the loan that clears it.
Your diagnosis
Max safe price: $35,943 (loan $29,943).
- SoonAim for 20% down to avoid going underwater on the loan
Currently ~17% down.
- LaterBuy 2-3 year-old used - new car loses 20% value driving off the lot
Your inputs
Edit any value - the diagnosis above updates instantly.
How the math works
The exact rules and formulas this flow applies - no black box.
- 1.Total transportation cost (loan + insurance) capped at 15% of take-home pay.
- 2.Total debt-to-income (existing + new car payment) capped at 36% of take-home (the standard DTI ceiling).
- 3.Recommended monthly loan payment = 10% of take-home (industry-standard 10/15/36 rule).
- 4.Max loan amount derived from payment via P = M x (1 - (1+r)^-n) / r.
- 5.Term flagged unsafe above 60 months - depreciation outruns equity build-up.
How to read your result
- Max car price < $20k with strong income: existing debt is consuming your headroom - clear it before buying.
- Required term > 60 months to "fit": pick a cheaper car, not a longer term.
- Insurance > $200/month suggests an expensive vehicle class. Plays directly into the 15% cap.
Common questions
Why include insurance in the calc?
Insurance is mandatory and varies 3x by car. Ignoring it lets a dealer sell you a "cheap" loan on a car that bankrupts your insurance budget.
Used or new?
2-3 year-old used hits the post-depreciation sweet spot. New makes sense only if you keep cars 8+ years.
Lease or buy?
Lease only if mileage is predictable, you replace cars often, and you have stable cash flow. Otherwise buy and keep.