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MoneyMath

Mortgage Affordability Calculator — How Much House Can I Afford?

Find the maximum home price you qualify for based on your income, existing debt, down payment, and mortgage rate. Uses the 28/36 DTI rule that most lenders apply, including property tax and insurance in the total.

🟢 Updated April 2026👤 Reviewed by MoneyMath Editorial⚡ Runs in your browser · inputs never leave your device
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Lender limits
Max home price
$405,000.00
14.8% down, $2,793.42/mo
Loan amount$345,000.00
Principal + Interest (/mo)$2,272.17
Property tax (/mo)$371.25
Insurance (/mo)$150.00
Total PITI + HOA$2,793.42
Front-end DTI used27.9%
Back-end DTI used31.9%
Conservative guidance:

Housing under 25% of gross = $2,500.00/mo. That leaves comfortable room for savings, travel, and surprises.

How lenders decide how much house you can afford

Every lender uses two ratios, called DTIs (debt-to-income):

  • Front-end DTI = (mortgage payment + taxes + insurance + HOA) ÷ gross monthly income. Cap: 28% conventional, 31% FHA.
  • Back-end DTI = (front-end + all other required monthly debts) ÷ gross monthly income. Cap: 36% conventional, 43-50% FHA with offsetting factors.

The calculator uses whichever cap produces a smaller home price — that's the real limit.

The 28/36 rule explained

Originally a Federal Reserve guideline from the 1930s, now the lender default. The logic: total housing ≤ 28% of income keeps mortgages payable through income volatility, and total debt ≤ 36% prevents a loan from swallowing your paycheck. Lenders may stretch to 43-45% on conforming loans with good credit + reserves.

Why "max" isn't "should"

Just because a lender approves you doesn't mean it's smart to borrow that much. Most financial planners recommend keeping housing under 25% of gross income. That leaves room for retirement savings (15%+), other debts, emergencies, and life. House-poor is a real condition — approved up to the max, then no money left for anything else.

What counts as "income"?

  • W2 base salary — 100% counts.
  • Bonus and commission — usually 2-year average required.
  • Self-employment income — 2 years of Schedule C, averaged. Often the hardest sell.
  • Rental income from other properties — 75% of gross rent counts.
  • Alimony, child support — only if documented for 3+ years of continuation.
  • Investment income — 2 years history, conservative haircut.

What counts as "debt"?

  • Student loans (even deferred — lender uses 1% of balance or 0.5%).
  • Auto payments.
  • Minimum credit card payments (not balances — just the monthly minimum).
  • Court-ordered alimony or child support.
  • Existing mortgage on another property.

Utilities, groceries, phone bills, insurance — not counted.

Things this calculator assumes

Standard conventional loan, no PMI (if less than 20% down, add ~$50-250/mo). Property tax fixed at your input rate — in reality tax reassesses after sale in many states. Insurance estimated — in FL/CA/TX actual is now often 2-3x that.

Frequently Asked Questions

What DTI do I actually need to get approved?

Under 36% back-end is comfortable for conventional. Up to 43% approved routinely on FHA. 45-50% possible with strong compensating factors (reserves, large down, high credit). Above 50% — very hard.

Does my credit score affect the max house price?

Indirectly — a lower credit score gets a higher rate. A 580 FHA rate vs a 760 conventional rate could mean 1-2%+ higher interest, which significantly reduces the home you qualify for at the same DTI. Run both rates to see the gap.

Should I include my spouse's income?

Yes if both are on the mortgage. Lender uses combined income and combined debts. If only one spouse is on the loan, only that person's income counts (but separate-property debts may not count either).

What about FHA vs conventional?

FHA allows 3.5% down with a 580 credit score and 43% back-end DTI. Conventional requires 5% down (3% for first-time buyers), 620+ credit, 36% DTI typical. FHA has higher fees (upfront MIP 1.75% + monthly MIP 0.55-1.05%) that persist for the life of the loan in most cases.

Why is my pre-approval higher than this calculator says?

Pre-approvals often use the maximum DTI limits (43-45%) without regard for the rest of your life. This calculator lets you dial in 28/36 — the actually-livable target.

What if I'm self-employed?

Lenders use your average net Schedule C income over 2 years — not gross revenue. Take-home after write-offs is the number. If you're newly self-employed, you may need a non-QM or bank-statement loan at higher rates.