№ 002 · Mortgage cluster
Affordability Calculator
How much house can you actually afford? Enter your income, debts, and down payment, and the 28/36 rule turns them into a maximum home price — with the catch that lenders care about most: which of the two debt-to-income limits is holding you back.
The 28/36 rule
Found your number? Run the full monthly payment in the Mortgage Calculator, or check the ratio behind the rule with the Debt-to-Income Calculator.
Income & debts01
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$
Loan & costs02
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Max home price
$428,748.65
Limited by 28% front-end$2,800.00/mo max
Max monthly payment$2,800.00/mo
Max loan amount$342,998.92
Down payment$85,749.73
Front-end (28%)$2,800.00
Back-end (36%)$3,100.00
Monthly debts$500.00
Max housing$2,800.00
- Principal & interest$2,281.98
- Property tax$393.02
- Insurance$125.00
| Principal & interest | $2,281.98 |
|---|---|
| Property tax | $393.02 |
| Insurance | $125.00 |
How it works · methodology
The math, in the open.
front-end cap = 28% × gross monthly income back-end cap = 36% × gross monthly income − monthly debts max housing payment H = min(front-end, back-end) max home price = (H − insurance/12 − HOA) ÷ [ (1 − down%) · f + tax rate ÷ 12 ]
- G
- Gross monthly income (annual ÷ 12)
- H
- Max housing payment — the binding cap
- f
- Monthly P&I per $1 of loan
- down%
- Down payment as a share of price
- tax rate
- Property tax, % of price per year
Assumptions & limits
- 28/36 are the conventional defaults; lenders flex — FHA runs ~31/43, and strong credit can stretch the back-end ratio toward 45–50%.
- PMI is not modeled — with less than 20% down, expect PMI on top, which lowers what you can afford.
- Property tax is a % of the price; insurance and HOA are fixed dollar amounts.
- An estimate to size your search, not a pre-approval or a guarantee.
Sources
By the MintNumber Editorial Team·Reviewed
Frequently asked
Questions about affordability
What is the 28/36 rule?
A long-standing lender guideline. The front-end ratio caps your housing payment at 28% of gross monthly income; the back-end ratio caps all of your debt payments — housing plus car, student, and credit-card minimums — at 36%. Whichever cap is lower sets how much house you can afford.
What’s the difference between the front-end and back-end ratio?
Front-end looks at housing alone (PITI). Back-end looks at every recurring debt payment together. If you carry other debt, the back-end cap usually binds first; if you carry almost none, the front-end cap does. This calculator uses whichever is the tighter limit and tells you which one.
What counts as monthly debt?
Recurring minimum payments that show on your credit report — car loans, student loans, personal loans, credit-card minimums, and things like child support. It does not include utilities, groceries, or insurance, which lenders don’t count toward the 36% back-end ratio.
Does this include PMI?
Not in this version. If you put down less than 20%, lenders usually add private mortgage insurance (PMI) on top, which lowers what you can afford. The number here assumes the down payment you enter and no PMI — treat a sub-20% result as a slightly optimistic ceiling.
How accurate is this versus a lender pre-approval?
It’s a solid first estimate built on the standard ratios. A real lender also weighs your credit score, employment history, and cash reserves, and may stretch the back-end ratio toward 43% (FHA) or higher with strong credit. Get pre-approved for the number you can actually shop with.