As you rule, you should not spend more than 28-31% of your pre-tax dollars on housing.
What is pretax?
It's common knowledge among financial experts that people shouldn't spend more than 28–31% of their pre-tax income on housing. We refer to this general rule of thumb as the 28/36 rule.
It indicates that housing costs should not account for more than 28% of your gross monthly income, and that the overall amount of debt payments, including those for housing and other obligations, should not exceed 36% of your gross monthly income.
Therefore you should not spend more than 28-31% of your pre-tax dollars on housing.