What Is the 40 Times Rent Rule? (And Is It Useful?)

The 40 times rent rule says a tenant's annual gross income should be at least 40 times the monthly rent. For a $2,000 apartment, that's $80,000 a year. It's the exact same math as asking for about 3.33 times the monthly rent in monthly income — the only difference is whether you quote the number in yearly or monthly dollars. It's a market convention used by landlords and property managers, not a law, and you can set your own multiple as long as you apply it consistently to every applicant.

The 40x rule and the 3x rule are the same test

Divide 40 by 12 and you get 3.33. That's it. A landlord asking for "40x the rent annually" is asking for a slightly stricter version of the familiar 3x monthly standard, and a landlord asking for 36x annually is asking for exactly 3x. Here's how the common multiples line up:

The 40x version also happens to line up neatly with the old "spend no more than 30% of income on housing" guideline, which is why it became the default in competitive rental markets. If you'd rather work the math the other way — plug in a rent and an income and see the ratio — use the rent-to-income ratio calculator.

Where you'll actually see 40x quoted

The annual framing is most common in large metro markets with professional management — New York City especially, where listings routinely state "40x rent" and applicants know what it means. It shows up in big-building leasing offices, corporate-managed buildings, and broker listings. Smaller landlords around the country tend to phrase the same requirement as "3x the monthly rent," partly because applicants with hourly or variable income find monthly numbers easier to verify.

Neither phrasing is more legitimate. If your applicant pool is used to hearing monthly multiples, use monthly multiples. If you're listing in a market where 40x is the vocabulary, say 40x. Just don't quote both in the same ad with mismatched numbers.

Guarantor versions: 80x and up

When an applicant doesn't hit the income threshold, the standard workaround is a guarantor (or co-signer) who signs the lease and is liable if rent isn't paid. Because a guarantor is usually carrying their own housing costs on top of yours, the convention is to require a higher multiple from them — commonly 80x the monthly rent annually, sometimes 75x or 90x. At $2,000 rent, 80x means a guarantor earning $160,000 a year.

Some management companies also require the guarantor to live in-state or in a nearby state, on the theory that it's easier to pursue a judgment. That's a business preference, not a legal requirement, and enforcing it rigidly can screen out otherwise qualified applicants. Whatever multiple you pick, verify the guarantor the same way you verify the tenant — income documents, credit, and identity. Here's how to screen a co-signer or guarantor properly.

Should you use 40x on a small portfolio?

A higher multiple is not automatically better. In a market where typical incomes don't support 40x on your rent, you'll sit on a vacancy for weeks and lose more than the risk you avoided. Run the numbers for your own unit: if 40x prices out most of your realistic applicant pool, 36x (3x) with strong verification and a solid rental history often produces a better outcome than 40x with a thin pool.

A few things to settle before you publish a number:

• Gross or net? Nearly every version of this convention uses gross (pre-tax) income, because that's what pay stubs, offer letters, and tax returns show. If you're unsure how to apply it to a specific rent figure, see what 3 times the rent actually means.
• Does "rent" include utilities? If your rent includes heat or water, the applicant's real housing cost is different from a comparable unit where it doesn't — this affects how you should read the multiple.
• Combined or per-person income? Decide whether roommates' incomes are added together or each must qualify individually, and use the same answer for everyone.
• What counts as income? Wages, self-employment income, retirement income, disability benefits, housing subsidies, and child support are all income. Some states and cities prohibit refusing applicants based on lawful source of income, so check your state and local rules before you exclude any category.

Applying it without creating fair housing problems

Write your income standard down before you advertise, publish it in the listing, and apply it to every applicant in the same way. Problems arise when a landlord enforces 40x for some applicants and waives it for others — that inconsistency is what makes a screening policy look like a pretext for discrimination under the federal Fair Housing Act. If you accept a guarantor for one applicant who falls short, offer the same option to everyone who falls short.

Also remember that an income multiple is only one input. A tenant at 38x with five years of on-time rent payments and a clean reference is usually a better bet than one at 45x with evictions on record. Income tells you whether rent is affordable; history tells you whether it will be paid. Once a tenant moves in, keeping clean per-lease payment records — Rentmark tracks rent per lease and issues PDF receipts — is what gives you that history for the next landlord, and for yourself.

This is general information, not legal advice; screening criteria, source-of-income protections, and deposit rules vary by state, and you can start with your state's security deposit laws before finalizing your application policy.