The short answer: on a $100,000 salary, the standard 28/36 affordability rule puts your maximum monthly housing cost at about $2,333 — which typically supports a home in the $350,000–$400,000 range depending on your down payment, interest rate, and local taxes. Below is the complete walkthrough: how the rule works, a worked 2026 example showing the actual arithmetic, and what moves the number up or down.
Educational example with stated assumptions — not mortgage advice. Lenders use their own underwriting; this shows how the widely used 28/36 guideline converts a salary into a home price.
The 28/36 rule, explained in plain English
Mortgage lenders and financial planners have long used two guardrails:
- Front-end ratio (28%): your total monthly housing cost — mortgage principal and interest, property taxes, homeowner’s insurance, and PMI if any (called PITI) — should be no more than 28% of your gross monthly income.
- Back-end ratio (36%): your total monthly debt payments — housing plus car loans, student loans, credit card minimums — should be no more than 36% of gross monthly income.
On $100,000 a year, that’s $8,333.33/month gross. So: housing ≤ 0.28 × $8,333.33 = $2,333.33/month, and all debts together ≤ 0.36 × $8,333.33 = $3,000/month.
Worked example: from salary to home price
Assumptions (stated): 30-year fixed mortgage at 6.5% (illustrative 2026 rate), 20% down payment, property tax 1.1% of home price per year, homeowner’s insurance $1,500/year, no PMI (20% down), and no other monthly debts for the baseline case.
Step 1 — your housing budget. $100,000 ÷ 12 = $8,333.33/month. Front-end cap: 0.28 × $8,333.33 = $2,333.33/month for PITI.
Step 2 — test a $350,000 home. With 20% down ($70,000), the loan is $280,000. At 6.5% over 30 years, the payment factor is about $6.32 per $1,000 borrowed (standard amortization formula): 280 × $6.32 = $1,769.79/month principal and interest.
Step 3 — add taxes and insurance. Property tax: 1.1% × $350,000 = $3,850/year = $320.83/month. Insurance: $1,500/year = $125/month. PITI = $1,769.79 + $320.83 + $125 = $2,215.62/month — under the $2,333.33 cap, with about $118/month of headroom.
Step 4 — check the back end. With no other debts, $2,215.62 is well under the $3,000 total-debt cap. But add $500/month in car and student-loan payments and the back-end math becomes $3,000 − $500 = $2,500 available for housing — the front-end cap ($2,333.33) still binds, so the answer barely changes. With $800/month in other debts, housing drops to $2,200/month — and now the back-end rule is the one that limits you.
Result: a ~$350,000 home with 20% down fits the rule cleanly. A $400,000 home with 20% down ($320,000 loan) needs PITI of about $2,514/month — over the $2,333 guideline unless you stretch the front-end ratio or have lower taxes/insurance.
What moves the number up or down
- Down payment: less than 20% down means a bigger loan and PMI (typically 0.3–1.5% of the loan per year) — both shrink the affordable price.
- Interest rate: at 7.5% instead of 6.5%, the same $280,000 loan costs about $1,958/month P&I — nearly $190 more, knocking roughly $25,000 off the affordable price.
- Property taxes: a 1.1% rate is moderate; in high-tax states the same home can cost hundreds more per month in PITI.
- Other debts: the back-end ratio is where car payments and student loans quietly cut your home budget.
Frequently asked questions
Can I afford a $400,000 house on $100K salary?
It’s a stretch under the 28% rule with 20% down — PITI runs about $2,539/month at 6.5% with moderate taxes, above the $2,333 guideline. With a larger down payment, lower taxes, or a lower rate, it can work. Check the worked math above with your own tax and insurance figures.
Is the 28/36 rule still used in 2026?
Yes — it’s still the baseline guideline in lender underwriting and planner guidance, though individual lenders approve ratios above 28/36 for strong borrowers. Treat it as a planning ceiling, not a promise of approval.
How much down payment do I need on $100K salary?
Twenty percent avoids PMI and gets the cleanest math — $70,000 on a $350,000 home. Many buyers put down less (3–10% is common for first-time buyers) and accept PMI; the trade-off is a higher monthly payment and a lower affordable price.
Does the 28/36 rule use gross or net income?
Gross (pre-tax) income. That’s one reason the rule can feel tight — the $2,333/month housing budget comes out of a paycheck that’s already reduced by taxes, so keep an emergency fund and real monthly budget alongside the ratio.
What salary do I need to afford a $500,000 house?
Roughly $125,000–$140,000, depending on down payment and taxes. A $500,000 home with 20% down needs PITI of about $3,165/month at 6.5% with moderate taxes — and $3,165 ÷ 0.28 × 12 ≈ $135,600 in salary to fit the front-end rule.
Run your exact numbers
Every market has different taxes, insurance, and rates — plug your real figures into our free mortgage calculator (it includes PITI and PMI) and see exactly which home price fits your $100K salary.