The 30 percent rule says rent should take no more than 30% of your gross income. It comes from HUD’s definition of cost burden: a household paying more than 30% of its income for housing is cost-burdened, and more than 50% severely cost-burdened (HUD PD&R). On $100,000 a year, 30% is $2,500 a month — below San Francisco’s HUD Fiscal Year 2027 one-bedroom Fair Market Rent of $3,003. The rule holds up as a warning line; it breaks down as a budget, because it ignores taxes and every other cost.
Where the rule comes from
Federal programs have long set rents as a share of income. Subsidized-housing rent was capped at 20% of income in the 1940s, at 25% under the 1969 Brooke Amendment, and at 30% from 1981 (HUD PD&R, Defining Housing Affordability). Over time the 30% threshold became the general affordability standard for renters and owners alike.
It was designed for low-income tenants in assisted housing — a ceiling on what the poorest households should be asked to pay — not as a budgeting target for every income level. HUD’s own researchers note the criticism: the same share of income leaves a high earner far more to live on than a low earner.
Where 30% works and where it does not
Using HUD FY2027 Fair Market Rents (40th-percentile gross rent, utilities included):
| Metro | 1-BR Fair Market Rent | Income needed at 30% | Share of $75,000 | Share of $100,000 |
|---|---|---|---|---|
| Wichita, KS | $823 | $32,920 | 13.2% | 9.9% |
| Phoenix, AZ | $1,493 | $59,720 | 23.9% | 17.9% |
| Austin, TX | $1,530 | $61,200 | 24.5% | 18.4% |
| Dallas, TX | $1,536 | $61,440 | 24.6% | 18.4% |
| Nashville, TN | $1,650 | $66,000 | 26.4% | 19.8% |
| Seattle, WA | $2,180 | $87,200 | 34.9% | 26.2% |
| New York, NY-NJ | $2,729 | $109,160 | 43.7% | 32.7% |
| San Francisco, CA | $3,003 | $120,120 | 48.0% | 36.0% |
Source: HUD FY2027 Fair Market Rents (91 FR 56156). Income needed = Fair Market Rent × 12 ÷ 0.30.
At $75,000 a single renter is under the line in five of these eight metros. In New York, every single earner below $109,160 is cost-burdened at Fair Market Rent; in San Francisco, the line is $120,120. A San Francisco studio ($2,574) is still 30.9% of $100,000.
The gross vs take-home problem
The rule uses gross pay, but rent comes from take-home pay. A single renter on $75,000 in New York City keeps $55,312 after 2026 federal, state, city and payroll taxes — $4,609 a month. A one-bedroom at Fair Market Rent takes 59.2% of that. In Austin, where Texas does not tax wages, the same rent share of take-home is 29.8%.
That is why MoveMath reports what is left after all modeled costs. On $75,000, the New York renter keeps $1,403 a year; the Austin renter keeps $24,665.
Applying the rule to a decision
Step 1: Find your 30% limit. $90,000 × 0.30 ÷ 12 = $2,250 a month.
Step 2: Compare it with the Fair Market Rent for the size you need. Austin two-bedroom: $1,817, under the limit. New York two-bedroom: $2,971, over it.
Step 3: Run the full budget. For a single renter on $90,000 in a two-bedroom, Austin leaves $31,774 a year after 2026 taxes, food, one car, sales tax and an estimate for other spending; New York leaves $7,588. The rent test tells you New York is a stretch; the budget tells you by how much. Try it in the relocation budget planner.
When to go above 30%
Spending more than 30% is not automatically a mistake. It can make sense when:
- Your income is likely to rise soon.
- Living in the city removes other costs, such as a car (the budget assumes one).
- You have checked the full budget and what is left still covers savings, health insurance and debt payments.
Treat the rule as a flag to look closer, then check the numbers in the rent affordability calculator. See how rent fits into whole budgets on the Austin, San Francisco and Wichita pages, or read how much rent you can afford for income tables by metro.