Mortgage lenders are chiefly concerned with your ability to repay the mortgage. To determine if you qualify for a loan, they will consider your credit history, your monthly gross income and how much cash you'll be able to accumulate for a down payment. So how much house can you afford? To know that, you need to understand a concept called "debt-to-income ratios."

Debt-to-income ratios
The standard debt-to-income ratios are The housing expense, or front-end ratio and the total debt-to-income, or back-end ratio.

Debt-to-income Ratios

Front-end Ratio The housing expense, or front-end ratio, shows how much of your gross (pretax) monthly income would go toward the mortgage payment. As a general guideline, your monthly mortgage payment, including principal, interest, real estate taxes and homeowners insurance, should not exceed 28 percent of your gross monthly income. To calculate your housing expense, multiply your annual salary by 0.28, then divide by 12 (months). The answer is your maximum housing expense. Maximum housing expense = annual salary x 0.28 / 12 (months) Back-end Ratio The total debt-to-income, or back-end ratio, shows how much of your gross income would go toward all of your debt obligations, including mortgage, car loans, child support and alimony, credit card bills, student loans and condominium fees. In general, your total monthly debt obligation should not exceed 36 percent of your gross income. To calculate your debt-to-income ratio, multiply your annual salary by 0.36, then divide by 12 (months). The answer is your maximum allowable debt-to-income ratio. Maximum allowable debt-to-income ratio = annual salary x 0.36 / 12 (months)

Example
Take a home buyer who makes $40,000 a year. The maximum amount for monthly mortgage-related payments at 28 percent of gross income would be $933. ($40,000 times 0.28 equals $11,200, and $11,200 divided by 12 months equals $933.33.)

Furthermore, the lender says the total debt payments each month should not exceed 36 percent, which comes to $1,200. ($40,000 times 0.36 equals $14,400, and $14,400 divided by 12 months equals $1,200.)

Example The following chart shows your maximum monthly payment and maximum allowable debt load based on your gross annual income (remember, gross income is pre-tax income): Debt-to-income ratio examples Gross income 28% of monthly 36% of monthly $20,000 $467 $600 $30,000 $700 $900 $40,000 $933 $1,200 $50,000 $1,167 $1,500 $60,000 $1,400 $1,800 $80,000 $1,867 $2,400 $100,000 $2,333 $3,000 $150,000 $3,500 $4,500 Here's a look at typical debt ratio requirements by loan type: • Conventional loans: Housing costs: 26 to 28 percent of monthly gross income. Housing plus debt costs: 33-36 percent of monthly gross income. • FHA loans: Housing costs: 29 percent of monthly gross income. Housing plus debt costs: 41 percent of monthly gross income. Taxes and Insurance In addition, lenders include the cost of taxes and insurance when calculating how much house you can afford: • Real estate taxes: Because property taxes are part of your monthly mortgage payment, it is important to get an estimate of what yours would be. Ask your real estate agent or tax office for the rates that apply in the area you want to buy. • Homeowners insurance: You must insure your property to obtain a mortgage. You can get an estimate of insurance costs from an insurance agent or insurance company. Be sure to inquire about special requirements for hazard insurance, such as mandatory coverage for floods, earthquakes, or wind in coastal areas. If you put down less than 20 percent of your home's value, you also will have to obtain mortgage insurance or take out a second loan, called a piggyback loan, to bring the first mortgage down to 80 percent of the purchase price. Both alternatives will raise your monthly payment.