Calculating the estimated mortgage payment...

Several formulas exist to help determine how much a lender will allow a consumer to borrow. One of the more accurate formulas is a front- and back-end ratio. It states that the buyer can afford as much as 28 percent of his or her gross-monthly income toward the monthly mortgage payment, assuming that the consumer's other debt payments(credit cards, car loans, student loans, etc...) are less than or equal to 8 percent of his or her gross-monthly income.

To better understand this formula, assume a gross-family income of $5,000 a month. The front-end ratio or maximum monthly mortgage payment is (28 percent of $5,000) $1,400. The back-end ratio is (8 percent of $5,000) $400. Therefore, the buyer can afford a $1,400.00 monthly mortgage payment as long as monthly debt payments are less than or equal to $400. If debt payments exceed the back-end ratio, it will reduce the monthly mortgage payment dollar for dollar. For example, if debt payments are $500, the maximum monthly mortgage payment a person could afford would be reduced to $1,300.