How the 3x Rent Calculator Works

One calculation engine produces every number on this site, from the homepage calculator to the tables on the rent pages. This page documents what it does so you can check it.

Income needed

income needed a year   = monthly rent x yearly multiple
income needed a month  = income needed a year / 12

Each rule is stored as a yearly multiple of the monthly rent, which keeps the arithmetic in whole numbers:

• 2x the rent a month = 24x a year
• 2.5x a month = 30x a year
• 3x a month = 36x a year
• 3.5x a month = 42x a year
• 4x a month = 48x a year
• 40x a year, the New York City rule, = 3.33x a month

Pay periods

every 2 weeks  = income needed a year / 26
a week         = income needed a year / 52
an hour        = income needed a year / (hours a week x 52)

Hourly figures assume 52 paid weeks. At 40 hours a week that is 2,080 hours a year. Weekly, biweekly and hourly amounts are rounded up to the cent, so a wage shown as the minimum always reaches the requirement.

Rent as a share of income

rent share = 12 / yearly multiple

At 3x that is 33.3%. At 2.5x it is 40%, at 2x it is 50%, and at 40x it is exactly 30%.

Do I qualify?

monthly income      = your pay converted to a month + other household income
times the rent      = monthly income / monthly rent
qualifies           = monthly income >= income needed a month
highest rent        = monthly income x 12 / yearly multiple
shortfall           = income needed a month - monthly income

Pay is converted to a month as follows: a yearly salary is divided by 12, a biweekly paycheck is multiplied by 26 and divided by 12, a weekly paycheck is multiplied by 52 and divided by 12, and an hourly wage is multiplied by weekly hours and by 52, then divided by 12. The highest rent is rounded down to the dollar.

What the calculator assumes

• Income is gross, before taxes and deductions. If your landlord uses take-home pay, enter that figure instead.
• The rent is the monthly rent on the lease. Add recurring charges such as parking if the landlord counts them.
• Household members' incomes are added together. Some landlords screen each adult separately.

What it does not do

It does not estimate taxes or take-home pay, and it does not look at debt, credit or rental history. Passing the income test is one part of an application, and it does not show that a rent fits your budget. The 30% rule guide covers the budget side.