The 30% Rule vs the 3x Rent Rule: How Much of Your Income Should Go to Rent

Two rules of thumb dominate the question of how much rent is too much. The 30% rule is the government’s affordable housing measure. The 3x rule is the landlord’s screening test, and the 3x rent calculator runs it for any rent. They sound alike and give different answers.

The two rules side by side

The 30% rule says housing should cost no more than 30% of gross income.

The 3x rule says gross income should be at least 3 times the rent, which caps rent at 33.3% of income.

The 3x rule is the looser of the two. Someone who exactly meets it is spending a bit more than the 30% rule allows.

Yearly salary	Rent at 30%	Rent at 3x	Difference
$36,000	$900	$1,000	$100
$48,000	$1,200	$1,333	$133
$60,000	$1,500	$1,666	$166
$90,000	$2,250	$2,500	$250
$120,000	$3,000	$3,333	$333

Going the other direction, a $1,500 apartment takes a $54,000 salary to pass 3x and a $60,000 salary to stay within 30%.

Where the 30% rule comes from

It began in public housing. In 1969 Congress passed the Brooke Amendment, which capped rent in public housing at 25% of a tenant’s income. In 1981 the cap was raised to 30%.

From there the figure spread into a general yardstick. Federal statistics now call a household cost burdened when housing takes more than 30% of income and severely cost burdened above 50%. HUD’s research office describes the history in Rental Burdens: Rethinking Affordability Measures.

One detail gets lost: the federal measure counts utilities as part of housing cost. Rent alone at 30% is already over the line once the electric bill is added.

Where the 3x rule comes from

Landlords needed a test they could run in seconds and apply to everyone. Multiplying the rent by 3 fits. It sits near the 30% standard, the arithmetic is simple, and a single cutoff for all applicants is easy to defend. The 3x rent rule guide covers how it is applied.

The rules serve different people. The landlord’s question is whether you are likely to pay. The 30% rule asks whether paying leaves you enough to live on.

The 40x rule is the 30% rule

New York City landlords ask for a yearly income of 40 times the monthly rent. Twelve months of rent against 40 months’ worth of income is exactly 30%.

So the 40x rule and the 30% rule are the same test written two ways. The 40x rent calculator shows the salary for any rent.

What both rules miss

Each one looks at gross income and nothing else.

Neither accounts for debt, the way a lender’s debt-to-income ratio does. A renter with $800 a month in loan payments has far less room than one with none, at the same salary and the same rent.

Taxes are left out too. Thirty percent of gross pay is a larger share of take-home pay, and the gap depends on where you live.

And neither scales well. A full-time worker at the federal minimum wage earns $15,080 a year, and 30% of that is $377 a month. Thirty percent of a $30,000 income leaves $1,750 a month for everything else before taxes. Thirty percent of $150,000 leaves $8,750. The low earner is stretched at a ratio the high earner would barely notice, which is the main criticism in the HUD article above.

Which one to budget by

Use the 3x rule to find out what you will be approved for. Use the 30% rule, or your own budget, to decide what to sign.

A workable method:

1. Find your approval ceiling: gross monthly income divided by 3.
2. Find your 30% figure: gross monthly income times 0.3. Subtract typical utilities if the rent does not include them.
3. List your fixed monthly costs: debt payments, insurance, transport, childcare.
4. Check the rent against your take-home pay with those costs removed.

If step 4 looks thin at the approval ceiling, aim closer to the 30% number. If you carry no debt and your other costs are low, renting at the 3x ceiling can be reasonable.

The 3 times the rent chart lists both figures for each rent from $500 to $5,000, and gross vs net income explains why approval and affordability use different pay numbers.