How to Calculate How Much House You Can Actually Afford

The bank’s answer vs. your answer

Lenders use two ratios:

• Front-end ratio (housing ratio): housing costs ÷ gross monthly income. Conventional loans typically allow up to 28%.
• Back-end ratio (debt-to-income, DTI): all monthly debt payments ÷ gross monthly income. Usually capped at 36–43% (up to 50% for some loan types).

On $100,000 income ($8,333/month), 28% = $2,333/month for housing. That might qualify you for a ~$380,000–$420,000 home depending on rates and taxes. But the bank’s maximum is not your target. Banks approve the largest loan you’ll probably repay — their incentive is loan volume, not your financial comfort. Your target should be lower.

The real calculation: total cost of ownership

PITI is just the start. The true monthly cost of a house:

• P — Principal & Interest: the mortgage payment itself. Use current rates, not hopeful ones.
• T — Property Taxes: 0.5–2.5% of home value annually depending on state — $300,000 at 1.5% = $375/month, and they rise.
• I — Insurance: homeowners insurance, $150–$300/month typical, rising with climate risk in many states.
• PMI: if under 20% down, add 0.5–1% of loan annually.
• HOA: $0–$500+/month — verify before falling in love with the house.
• Maintenance: budget 1% of home value per year ($300,000 → $250/month). Older homes: more.
• Utilities delta: bigger house = bigger bills. Budget the increase honestly.

Add them all. That’s your monthly housing cost — often 30–50% above the mortgage payment alone. If that total exceeds ~28% of gross income (or ~35% in high-cost areas with eyes open), the house is too much.

The comfort-first framework

Instead of “what’s the max I qualify for,” ask:

1. The sleep test: if one income disappeared (job loss, new baby, illness), could you still cover the house for 6 months from emergency savings + remaining income? If not, it’s too much house.
2. The 25% rule: many financial planners recommend total housing ≤25% of take-home pay (not gross) on a 15-year mortgage. Aggressive? Yes — and it’s the rule that keeps buyers comfortable instead of stretched.
3. The life budget test: after housing + all other costs + 20% savings, is there money left for actual living? A house that kills your savings rate and fun money isn’t affordable — it’s a cage with granite countertops.
4. The 5-year test: will you stay 5+ years? Buying rarely beats renting under 5 years once transaction costs (8–10% round trip) are counted.

Worked example

Household income: $120,000 ($10,000/month gross, ~$7,800 take-home after taxes/benefits).

• Bank says: 28% of gross = $2,800/month housing → ~$450,000 home at 7% rates.
• Total-cost reality on $450,000: mortgage ~$2,400 + taxes $560 + insurance $200 + maintenance $375 = ~$3,535/month — 45% of take-home. House poor.
• Comfort target (25% of take-home): ~$1,950/month all-in → roughly a $300,000–$330,000 home.

The gap between $450,000 (bank max) and $320,000 (comfort) is the difference between stress and security. In high-cost markets the comfort number may be unattainable — that’s information, not failure; it means renting longer, raising income, relocating, or buying smaller.

Hidden costs first-time buyers always miss

Beyond PITI, first-time buyers consistently underestimate:

• Closing costs: 2–5% of the purchase price — on a $350,000 home, that’s $7,000–$17,500 due at closing, on top of the down payment.
• Immediate repairs and setup: even inspected homes need things — locks changed, minor fixes, furniture for extra rooms. Budget $3,000–$5,000 minimum.
• Moving costs: $1,000–$5,000 depending on distance and how much stuff you own.
• Utility deposits and setup fees: small individually, annoying collectively.
• The “homeowner premium”: studies suggest homeowners spend 1–3% of home value annually on maintenance and improvements — much of it unplanned. That first year always costs more than projected.

Add these to your cash-needed calculation: down payment + closing costs + $5,000–$10,000 buffer. Buyers who drain every dollar to close end up putting the first repair on a credit card — starting homeownership in debt.

Factors that change your number

• Interest rates: every 1% rate change moves affordability ~10%. At 7% vs. 4%, the same payment buys dramatically less house.
• Down payment size: bigger down = smaller loan = lower payment + no PMI. Our down payment savings guide covers building it.
• Other debts: $800/month in car + student loan payments directly reduces mortgage capacity via DTI. Killing debts before buying effectively raises your house budget.
• Income stability: variable or single income → be more conservative than the ratios suggest.
• Future plans: kids (daycare can exceed a mortgage — in many US cities infant care costs $15,000–$25,000 per year!), career changes, aging parents — buy for the life you’re building, not just today’s spreadsheet. A house that’s affordable now but unaffordable after daycare starts is a trap; model the next five years, not just the next five months.
• Credit score: a 760+ score versus 650 can mean 1%+ rate difference — tens of thousands over the loan. Build credit before house hunting (see our personal finance foundations and credit improvement guide).

The CFPB’s homebuyer tools and HUD-approved counselors offer free, unbiased guidance — use them before you fall in love with a listing.

The bottom line

Calculating how much house you can actually afford: start with the bank’s ratios (28%/36%), then compute true total ownership cost (PITI + PMI + HOA + 1% maintenance + utilities), then apply the comfort tests — 25% of take-home, the sleep test, the life-budget test. Buy the house that passes those, not the maximum the lender approves. Future you — sleeping soundly, saving steadily, actually enjoying the home — will thank present you for the restraint and the wisdom. The goal isn’t the biggest house you can technically finance; it’s the right house that leaves room for savings, life, and sleep.

Frequently Asked Questions

How much house can I afford on my salary?

A rough starting point: 3–5× gross annual income, refined by the 28/36 ratios. But compute total ownership cost (taxes, insurance, maintenance, HOA) and keep it near 25% of take-home for comfort.

What is the 28/36 rule?

Lender guidelines: housing costs ≤28% of gross monthly income, total debt payments ≤36%. They’re maximums for approval — not targets for comfort.

How much should I spend on housing per month?

Many planners recommend ≤25% of take-home pay for total housing costs (mortgage, taxes, insurance, maintenance). The bank’s 28%-of-gross maximum usually feels tight in practice.

Does my credit score affect how much house I can afford?

Yes — significantly. Better scores mean lower rates, and 1% rate difference changes purchasing power ~10%. Build your score before house hunting.

Should I buy the maximum the bank approves?

Almost never. Banks approve the maximum you’ll probably repay; their incentive is loan volume. Buy to your comfort number — the house that leaves room for savings, emergencies, and actually living.