40x rule formula
Multiply monthly rent by 40 to estimate the annual gross income target. A $2,000 apartment maps to about $80,000 in annual gross income under this rule.
Monthly rent x 40 = annual income target
Why it matches the 30 percent rule
The 40x rule is another way to express a rent share close to 30 percent of gross income. It is common in apartment screening because it is easy to check from annual pay.
What it does not include
The rule does not include utilities, debt, savings, application standards, guarantors, credit checks, deposit rules, or local housing law. Treat it as a screening estimate only.