Rent-to-income ratio compares the rent to an applicant’s income to gauge affordability. A widely used benchmark is that rent should be no more than about 30% of gross monthly income — equivalently, that income should be around 3× the rent — though every landlord sets their own threshold.
It’s one input in screening, not the whole picture: savings, other debts, and rental history matter too. Whatever benchmark you choose, apply it consistently to every applicant and write it down — both because that’s fairer and because inconsistent standards can create fair-housing exposure.