Lenders also calculate the "back-end ratio." It includes all debt commitments, including car loan, student loan and minimum credit card payments, together with your house payment. Lenders prefer a back-end ratio of 36 percent or less.
Ratios aren't carved in stone
Those recommended ratios (28 percent front-end and 36 percent back-end) aren't ironclad. In many cases, lenders approve applicants with higher debt-to-income ratios. Under the "qualified mortgage rule," federal regulations give legal protection to well-documented mortgages with back-end ratios (all debts, including house payments) up to 43 percent.
"That's been one of the bigger drivers (of affordability) because that is basically drawing a box around what's a qualified mortgage," says Tim Skinner, home lending sales and service manager for Huntington Bank in Columbus, Ohio. "A large portion of the lending community has decided to stay in that box."
If you have a good credit history, you are likely to get a lower interest rate, which means you could take on a bigger loan. The best rates tend to go to borrowers with credit scores of 740 or higher.
See how your credit score affects your mortgage rate.
With a larger down payment, you will likely need to take on a smaller loan and can afford to buy a higher-priced house.
Money from your savings that you give to the home's seller. A mortgage pays the rest of the purchase price. It's usually expressed as a percentage: On a $100,000 home, a $13,000 down payment would be 13 percent.
You don't need to have a perfect credit score or a 20 percent down payment to qualify for a mortgage. Some lenders will accept down payments as small as 3 percent. Federal Housing Administration-insured mortgages have a minimum down payment of 3.5 percent.
See five mortgages that require little or no down payment.
While the lender's guidelines are a good place to start, consider how your lifestyle affects how much of a mortgage you can take on. For instance, if you send your children to a private school, that is a major expense that lenders don't typically account for. Or maybe you like to spend a lot on dining out or clothes. And if you live in a city with good public transportation, such as San Francisco or New York, and are able to rely on public transportation, you can likely afford to spend more on housing.
Consider all your options
Look into various state government programs that provide certain concessions, especially for first-time homebuyers. There also are programs that you might qualify for based on your income or occupation. You may be able to get assistance with your down payment so you can take on a smaller loan.
Nikitra Bailey, executive vice president for the Center for Responsible Lending in Durham, North Carolina, says, "A lot of creditworthy borrowers have been unable to secure mortgages in the tighter mortgage environment. We are hopeful that these efforts will open up credit for borrowers who are deserving so that we will see an increase in first-time homebuyers going forward."
Don't overload yourself
Be careful. It's wise to give yourself breathing room financially. You don't have to deplete your savings, and you don't have to make the maximum monthly payment that you qualify for.
Why is it wise to spend less than you can afford? As a homeowner, you will face unexpected expenses, such as a leaky roof or a failed water heater. You will have to pay for maintenance. You might even face a job loss.
"When gas prices started to go up (during the housing downturn) and people were maxed out on their homes, that's when we started seeing a lot of the defaults happen," says Kathy Cummings, homeownership solutions and education executive for Bank of America. "There were a lot of other economic factors going into it, but if you are maxing yourself out on your home, you can't absorb some of those impacts."