To qualify for a mortgage, lenders typically require that you have a debt-to-income ratio of "43/49."

This means that no more than 43% of your total monthly income (from all sources, before taxes) can go toward your new mortgage payment, and no more than 49.99% of your monthly income can go toward your total monthly debt (including your mortgage payment).

VA and FHA loans even allow for higher debt ratios on a case by case basis.