Front-End Ratio. Typically, lenders cap the mortgage at 28 percent of your monthly income. To determine your front-end ratio, multiply your annual income by 0.28, then divide that total by 12 for your maximum monthly mortgage payment.
FHA Requirements Debt-to-Income Ratio Guidelines. In order to prevent homebuyers from getting into a home they cannot afford, FHA requirements and guidelines have been set in place requiring borrowers and/or their spouse to qualify according to set debt to income ratios.
USDA eligibility is based on a combination of household size and geography, in addition to the typical mortgage approval standards such as income and credit score verification. USDA eligibility.