The housing expenses of the front-end DTI ratio measure include more than just your mortgage. It also includes property taxes, homeowners insurance, and mortgage insurance, if applicable.

A steep rise in other housing-related costs, such as insurance, utilities, and property taxes, is making homeownership even more unaffordable for Americans.

The NAR calculates qualifying income as monthly mortgage payment (with principal and interest) multiplied by 4 (which reverses the 25% ratio on monthly housing expense to gross monthly income ...