The 28/36 rule is one of the oldest and most reliable guidelines in personal finance — a simple formula that tells you how much house you can comfortably afford without becoming “house poor.” Lenders still use it. Financial advisors still recommend it. And if you follow it, you’ll sidestep the single biggest mistake first-time buyers make: buying more house than their life can handle.
Want to see how the 28/36 rule applies to your actual numbers? Run your income and debts through our free home affordability calculator — it uses the 28/36 framework to show you exactly what fits your budget.
What is the 28/36 rule?
The 28/36 rule is a simple formula lenders and financial planners use to measure how much debt you can comfortably carry. It breaks down into two parts:
- 28% — Your total monthly housing costs (mortgage, property taxes, insurance, HOA fees) should stay under 28% of your gross monthly income.
- 36% — Your total monthly debt (housing + car loans + credit cards + student loans + everything else) should stay under 36% of your gross monthly income.
“Gross monthly income” means your total earnings before taxes. If you earn $6,000/month, the rule says your housing costs should stay under ~$1,680 and your total debts under ~$2,160.
That’s it. Two numbers. No fancy math. It’s one of the most durable rules in personal finance because it works across every income level and every market.
Where does the 28/36 rule come from?
The 28/36 rule dates back to the 1970s, when lenders were looking for a simple, reliable way to measure borrower risk. After decades of data, researchers found that borrowers who stayed under these thresholds were dramatically less likely to default on their mortgages — even during recessions.
It became the standard lending benchmark through the 1980s and ’90s. Today, most lenders will let you push past 36% on the back-end ratio (sometimes up to 50%), but the 28/36 rule remains the gold standard for comfortable affordability — not just the maximum you can qualify for.
Breaking down each ratio
The 28%: your front-end ratio (housing only)
The “28” in 28/36 refers to your housing expense ratio — the percentage of your gross monthly income that goes toward your home. It includes:
- Principal and interest on your mortgage
- Property taxes
- Homeowners insurance
- HOA dues or condo fees
- PMI (private mortgage insurance), if applicable
Lenders sometimes call this “PITI” (Principal, Interest, Taxes, Insurance). If you earn $6,000/month, the 28% rule says your full PITI should stay at or under $1,680.
The 36%: your back-end ratio (total debt)
The “36” is your total debt-to-income ratio — the percentage of your gross monthly income that goes toward all recurring debt, including:
- The full PITI housing payment from above
- Car loans and leases
- Credit card minimum payments
- Student loans
- Personal loans
- Child support or alimony
If you earn $6,000/month, total debts should stay under ~$2,160. That leaves you ~$3,840/month for everything else — groceries, utilities, childcare, savings, retirement, and a little fun.
Learn more in our guide to debt-to-income ratio.
28/36 rule examples by salary
| Annual salary | Gross monthly | Max housing (28%) | Max total debt (36%) |
|---|---|---|---|
| $50,000 | $4,166 | $1,167 | $1,500 |
| $75,000 | $6,250 | $1,750 | $2,250 |
| $100,000 | $8,333 | $2,333 | $3,000 |
| $125,000 | $10,416 | $2,917 | $3,750 |
| $150,000 | $12,500 | $3,500 | $4,500 |
| $200,000 | $16,666 | $4,667 | $6,000 |
These are ceilings, not targets. The healthiest buyers land below both numbers — giving them breathing room for saving, investing, and life’s surprises.
Why the 28/36 rule still works
1. It accounts for real life
The rule isn’t just about whether you can make payments. It builds in room for groceries, utilities, childcare, transportation, savings, and emergencies. Buyers who blow past 36% DTI often find themselves one emergency away from financial trouble.
2. It protects you from lender optimism
Modern lenders will happily approve you at 43% or even 50% DTI if your credit and cash reserves are strong. That doesn’t mean it’s a good idea. The 28/36 rule is a guardrail against your future self saying yes to a home that looks affordable on paper but crushes your quality of life.
3. It scales with any income
Whether you earn $40,000 or $400,000, the percentages still work. The rule is deliberately relative so it holds up across income levels and geographic markets.
4. It’s simple enough to actually use
Personal finance rules only matter if people actually use them. The 28/36 rule survives because it’s two numbers, easy to remember, and easy to check in 30 seconds on the back of a napkin.
When to break the 28/36 rule (carefully)
The 28/36 rule is a guideline, not a law. There are legitimate situations where going over can make sense:
You’re buying in a high-cost market
In expensive markets (San Francisco, NYC, Miami, Boston), nearly everyone spends 30–40% on housing. If rent is already eating 35% of your income, buying at 32% might still be an improvement — especially if it builds equity.
Your income is growing fast
If you’re early in a career with predictable salary increases (law, medicine, tech), stretching today can make sense because your income will catch up. Just don’t assume future income you haven’t earned yet.
You have no other debt
If your back-end ratio is under 36% because you have zero other debt, you can push housing past 28% without blowing the total. A 32% front-end + 32% back-end is healthier than a 28% front-end + 42% back-end.
You have huge cash reserves
6–12 months of emergency savings in the bank gives you cushion to handle a higher payment. Lenders call this a “compensating factor” and will approve higher DTI for strong savers.
When to stay far under the 28/36 rule
Flip side: there are situations where you should aim for 22/30, not 28/36:
- Variable or commission income — your income isn’t predictable
- Single-income household — no backup earner if something happens
- High childcare or medical costs — real expenses that don’t show on a credit report
- Saving aggressively for retirement — a house payment shouldn’t steal from your 401(k)
- Planning to have kids soon — one parent may go part-time or leave the workforce
- Student loans about to come out of deferment — future debt not yet on your report
Calculating your 28/36 in 60 seconds
- Write down your gross monthly income (before taxes)
- Multiply by 0.28 → that’s your housing ceiling
- Multiply by 0.36 → that’s your total debt ceiling
- Add up your current debt payments (cars, credit cards, student loans, alimony)
- Subtract current debts from the 0.36 number → that’s your actual mortgage headroom
Example: You earn $7,500/month. Housing ceiling = $2,100. Total debt ceiling = $2,700. You have $650 in existing monthly debts. Your max mortgage payment is the lower of: $2,100 (front-end) or $2,050 ($2,700 – $650 back-end). So your real number is $2,050.
Our affordability calculator does this math automatically and shows you the exact home price that fits within the rule.
What the 28/36 rule doesn’t include
Even when you follow the rule perfectly, there are costs the formula ignores:
- Maintenance and repairs — budget 1–2% of home value per year
- Utilities — often 2–3x what you paid renting
- Furniture and moving — easy to drop $10,000–$20,000 on a new home
- Closing costs — 2–5% of purchase price upfront
- Lifestyle inflation — new house, new commute, new everything
The smart move: follow the 28/36 rule as a ceiling, then leave another 5–10% of your income as buffer. Your future self will thank you.
Beat the rule: get more house without stretching
Here’s a trick that improves your 28/36 math without changing your salary: lower your purchase price. And the fastest way to lower your effective purchase price is to get money back when you buy. When you use the Beycome buyer program, we rebate up to 2% of the purchase price back to you at closing. On a $400,000 home, that’s $8,000 you can apply to a bigger down payment (reducing your mortgage), closing costs, or a larger safety cushion — all of which improve your DTI.
See exactly how the rebate shifts your 28/36 numbers in our affordability calculator.
Bottom line: comfort beats maximum
The 28/36 rule isn’t about what you can buy — it’s about what you can comfortably buy. The best homeowners don’t stretch to the ceiling; they stay well below it. A mortgage at 28% feels great. A mortgage at 42% feels like a trap. The rule is the difference between owning a home you love and working two jobs to keep it.
Want to apply the 28/36 rule to your real numbers? Run your income, debts, and down payment through the Beycome affordability calculator — it’s built on the same rule lenders use.
Discover beycome title today!