The short answer: 30% of gross income, which is $1,500 if you bring home $5,000 a month before taxes. The useful answer is longer, because the 30% rule was written for 1980s housing subsidies, ignores your student loans, and quietly assumes your income is average — which, nationally, it now isn't: the average renter would need to earn about $10 more an hour to make the typical two-bedroom fit the rule. Here's what the rule says, where it came from, and when to override it.
Spend no more than 30% of gross monthly income on housing. Gross means pre-tax — $5,000 a month earns you a $1,500 rent ceiling regardless of what actually lands in your account. Cross the line and researchers call you "cost-burdened"; cross half your income and you're "severely cost-burdened," the category where one car repair becomes an eviction risk.
Three ratios cover the field. The classic 30% is the middle standard. The stricter 28% version comes from mortgage underwriting, where lenders cap total housing cost. And a looser one-third rule shows up as a paycheck heuristic — gross weekly pay times four is roughly your month, take a third of it. They're all within $100–$200 of each other at moderate incomes, which tells you something: precision isn't the point. Slack is.
It's federal law, sort of. In 1969 the Brooke Amendment capped public housing rent at 25% of income. Inflation ate away at that, and by 1981 Congress had raised the threshold to 30% of adjusted income, where federal housing programs have stayed since. Somewhere along the way the number escaped its subsidy context and became a general-purpose affordability test for a country that now rents by choice as often as necessity.
The rule's blind spots are features of its birth. It was meant to prevent subsidies from crowding out food and medicine for low-income households — not to advise a software engineer weighing a $2,400 loft. It ignores debt, local transit costs, family size, and whether you're paid in gross-income terms at all. Use it as a starting dial, not a verdict.
The table applies each rule across common income levels, using gross monthly income — the basis landlords screen on:
| Gross monthly income | Rent at 28% | Rent at 30% | Rent at 1/3 | What's left after 30% |
|---|---|---|---|---|
| $3,000 | $840 | $900 | $1,000 | $2,100 |
| $4,000 | $1,120 | $1,200 | $1,333 | $2,800 |
| $5,000 | $1,400 | $1,500 | $1,667 | $3,500 |
| $6,250 | $1,750 | $1,875 | $2,083 | $4,375 |
| $8,000 | $2,240 | $2,400 | $2,667 | $5,600 |
| $10,000 | $2,800 | $3,000 | $3,333 | $7,000 |
Notice the last column more than the rent columns. What the ratio actually protects is the remainder — the money that absorbs groceries, debt payments, and the emergency you didn't schedule. A $10,000 earner spending 35% on rent keeps more slack than a $3,500 earner spending 25%, which is why the rule bends at the extremes and the rent calculator shows the remainder, not just the cap.
One honest adjustment: run the rule on take-home pay too, and treat that as your real ceiling. On $5,000 gross, take-home is roughly $4,000 after taxes; 30% of that is $1,200 — a full $300 under the standard version. The gross version matches how landlords and programs measure you; the net version matches how life actually feels.
The uncomfortable context, from the National Low Income Housing Coalition's 2026 Out of Reach report: the national two-bedroom fair market rent is $1,806 a month, and affording it at the 30% standard takes a wage of $34.73 an hour, full-time. The average renter actually earns $24.84. Run the same arithmetic backward and the typical two-bedroom wants about $6,020 of monthly income — roughly $72,200 a year — while the average renter's wage supports about $1,292. That's not a budgeting failure; it's the market admitting the rule is aspirational in much of the country.
Which is why the 30% test has two different uses. As a planning tool for your next lease, it works fine. As a description of what renters can get, it fails often enough that census surveyors track cost-burdened households as a standard statistic.
Landlords don't use ratios — they use multiples. The standard screen is gross monthly income of 2.5× to 3× the rent, documented with pay stubs or an offer letter. For a $1,800 apartment, that's $4,500 to $5,400 a month. Some markets and corporate landlords add credit-score floors, and a few stretch to "3× after tax," which is meaningfully harder.
If you're near the line: a co-signer, a larger deposit, or two months' bank history can carry an application the income multiple would reject. And if you clear 3× comfortably, you've also cleared 33% — the landlords' test is looser than the advice.
Sometimes the spreadsheet says yes. The cases where going over is defensible:
The reverse cases matter too. Heavy debt service, irregular income, or a savings goal with a deadline all argue for 25% or less, even in a market that would approve you at three times the rent. The ratio is one input; the thing it proxies for — how much room is left after housing — is the real budget.
The lease number plus its entourage. Renter's insurance runs $15–$30 a month for a standard policy in much of the country. Utilities travel separately in many buildings — electric, gas, water, internet — and parking or laundry can add real money in some markets. Counting only contract rent is how a 30% lease becomes a 36% life. Add the extras before you compare units: two apartments $100 apart in rent can be equal once the meter bills arrive.
Enter your income, pick your rule — 28%, 30%, or a third — and see the rent ceiling plus what stays in your account every month.
Rent Calculator →Start at 30% of gross, sanity-check it against 30% of take-home, and adjust for debt, transit, and how much cushion you refuse to give up. Landlords will ask for three times the rent in income, the rule's own national arithmetic stopped adding up for average earners, and the honest goal was never the percentage — it's the slack underneath it. Run your number in the rent calculator, stress the leftovers in the DTI calculator, and price the insurance line with the renters insurance calculator before it surprises you.
The standard guideline is 30% of gross monthly income — $1,500 on a $5,000 paycheck. A stricter personal version uses 25-30% of take-home pay instead, which accounts for taxes before you budget. Either way, budget total housing cost (rent plus insurance, utilities, parking), not just the lease number.
The official version uses gross income — that's how federal housing programs define it. But your budget runs on net pay, so a take-home version of the same rule is more protective: 30% of net usually lands near 25% of gross. Pick one basis and stay consistent, or you'll drift without noticing.
It comes from U.S. housing policy: the Brooke Amendment set a 25% rent cap for public housing in 1969, and Congress raised the threshold to 30% of adjusted income in 1981. The figure stuck as the affordability benchmark even though it was written for subsidy programs, not market renters.
Most landlords screen for gross monthly income of 2.5 to 3 times the rent — a $1,800 apartment wants $4,500 to $5,400 documented — plus credit and reference checks. Meeting the 30% rule generally satisfies the income side of a typical application.
Then the rule is describing a market problem, not your failure. Nationally, the average renter earns $24.84 an hour while affording the typical two-bedroom at HUD's fair market rent takes $34.73 — a gap that forces many households above 30%. Your options are structural: roommates, longer commutes, or trading other budget lines consciously. Spending 35-40% with zero debt and no car can beat 28% with both.