What does 3x the rent mean?

It means your gross monthly income has to be at least three times the monthly rent before a landlord will approve your application. If the rent is $1,500, you need to show $4,500 a month, or $54,000 a year. The phrase describes income, not money due at signing. You do not pay three months of rent up front.

Landlords use the ratio as a quick test of whether rent will be a strain. At exactly 3x, rent takes one third of pay before taxes.

People mix this up with move-in costs, which are separate: usually the first month of rent plus a security deposit. Those are paid once. The income test is about what you earn every month. To see the income figure for any rent, use the 3x rent calculator.