Formula

Rent to income ratio = monthly rent / gross monthly income x 100

If rent is $1,650 and gross monthly income is $5,500, the ratio is 30 percent. If the same rent is checked against $4,500 income, the ratio is about 36.7 percent.

Quick ratio table

Gross monthly income$1,200 rent$1,600 rent$2,000 rent
$4,00030%40%50%
$5,50022%29%36%
$7,00017%23%29%

Use take-home pay as the second check

A ratio based on gross income can look fine while the monthly cash flow still feels tight. After the ratio check, subtract debts, utilities, insurance, transportation, savings, groceries, and a basic living buffer.

Helpful next step: Use the main rent affordability calculator to compare the ratio against take-home pay and move-in cash.