Why do apartments require 3x the rent?

Because it is a fast way to judge whether a tenant can keep paying. A renter who earns 3 times the rent spends about a third of gross income on housing, which leaves room for taxes, food, transport and a bad month. Landlords treat that cushion as protection against late payments and evictions.

The figure sits close to the federal affordability standard, which counts housing as affordable when it costs no more than 30% of gross income. Three times the rent works out to 33.3%.

It is also simple to apply. One multiplication gives a yes or no for every applicant, and using the same test for everyone helps a landlord stay within fair housing law. More on the history is in the 30% rule guide.