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Learning CenterThe 3-3-3 rule and the 28/36 rule, explained
The 3-3-3 rule is a personal budgeting tip: keep about three months of reserves, keep housing near 30% of take-home pay, and plan to stay three years. The 28/36 rule is a lending guideline: housing near 28% of gross income and total debts near 36%. Use one for comfort, the other for approval odds.
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What is the 3-3-3 rule for buying a house?
The 3-3-3 rule is a personal budgeting tip, not a lending rule. You'll see several versions online, but the most common one says:
- 3 months of reserves: keep at least three months of expenses (including the new house payment) in savings after closing.
- About 30% of take-home pay: aim to keep your housing payment near 30% of what actually hits your bank account.
- 3+ years in the home: buy when you expect to stay at least three years, so closing costs and moving expenses have time to pay off.
Some versions swap in "3% down payment" or "3 times your income" for the home price. The spirit is the same: buy a home you can keep comfortably, with a cushion, for long enough to make the costs worth it.
What is the 28/36 rule?
The 28/36 rule is a debt-to-income (DTI) guideline that lenders and housing counselors have used for decades:
28% front-end
Your total housing payment—principal, interest, taxes, insurance, mortgage insurance, and HOA (PITI)—at or below about 28% of gross monthly income.
36% back-end
All monthly debts—housing plus car, student loans, card minimums, and other obligations—at or below about 36% of gross monthly income.
Many loan programs allow higher ratios than 36% when credit, down payment, and reserves are strong, so 28/36 is a conservative comfort zone rather than a hard approval cutoff.
How are the 3-3-3 and 28/36 rules different?
| 3-3-3 rule | 28/36 rule | |
|---|---|---|
| Who uses it | Buyers planning their own budget | Lenders, counselors, and buyers |
| Income base | Take-home (net) pay | Gross pay, before taxes |
| Looks at | Savings cushion, comfort, time horizon | Payment and debts vs. income |
| Decides approval? | No | Partly—actual limits vary by program |
| Best use | "Should I buy, and how much?" | "What might a lender approve?" |
Because 3-3-3 uses take-home pay, it is usually stricter than 28/36. That is a feature: it accounts for taxes, retirement contributions, and health premiums that come out before you ever see the money.
What do both rules say on a $75,000 salary?
Illustrative example: $75,000 gross, about $4,800/mo take-home
28/36: gross monthly $6,250 → housing near $1,750, all debts near $2,250.
3-3-3: 30% of $4,800 take-home → housing near $1,440, plus about $12,000–$15,000 in savings after closing for three months of expenses.
The gap—roughly $300 a month—is the difference between what a guideline might allow and what may feel comfortable. Illustrative only, not a commitment to lend.
See how salary translates into price ranges in How much house can I afford? or run your own numbers in the affordability calculator.
What these rules are—and aren't
- They are quick sanity checks before you talk to a lender or start touring homes.
- They aren't a pre-approval. Underwriting looks at credit, income history, assets, the property, and program rules.
- They don't know your life. Childcare, commuting, or a big savings goal can make a "within the rules" payment feel tight. A paid-off car and low expenses can make a higher ratio fine.
- They ignore local costs unless you include them. Property taxes, insurance, and HOA dues change the payment on the same price—see the homebuying guide.
Our take: use 28/36 to understand what's possible and 3-3-3 to decide what's wise. Then get pre-approved so you know the real number. First time buying? Start with the first-time buyer guide.
How do I use both rules before I shop?
Start with take-home pay
Pull your last two pay stubs and find your true monthly net. Multiply by 0.30 for a 3-3-3 housing target.
Run the gross-income math
Multiply gross monthly income by 0.28 for housing and 0.36 for all debts. List every minimum payment from your credit report.
Use the lower number as your target
Shop around the more conservative payment; treat the higher number as your ceiling, not your goal.
Price in local costs
Ask for estimated property taxes, insurance, and HOA dues on homes you like—these can swing a payment by hundreds of dollars.
Count your cushion
Add down payment, closing costs, and three months of expenses. If savings fall short, adjust the price, use assistance, or give yourself a few more months.
Get pre-approved
Let a lender confirm what you qualify for, then decide where in that range you want to live.
Remember that a lower payment also leaves room for the things that make a house a home—furniture, repairs, and the occasional weekend away. A budget that only works on paper rarely works in real life.
Frequently asked questions
What is the 3-3-3 rule in real estate?
A budgeting tip: keep about 3 months of reserves after closing, keep housing near 30% of take-home pay, and plan to stay at least 3 years. It is not a lender rule.
What is the 28/36 rule?
A guideline that keeps housing near 28% of gross monthly income and total debts near 36%. Many programs allow higher ratios with strong credit and reserves.
Do lenders use the 3-3-3 rule?
No. Lenders use debt-to-income ratios, credit, assets, and program guidelines. 3-3-3 is a personal comfort check.
Which rule should I follow?
Use 28/36 to estimate what you might be approved for and 3-3-3 to decide what feels sustainable. The lower of the two is usually the safer target.
Can I be approved above 36% DTI?
Often yes. Automated underwriting for conventional, FHA, and VA loans can approve higher DTIs when the rest of the file is strong.
Educational answers only—not a loan offer or commitment to lend. Examples are illustrative only, not a commitment to lend.
Turn rules of thumb into a real number
A pre-approval shows what you qualify for; a conversation helps decide what fits. Call a loan officer at (480) 233-7897.