Any reputable real estate broker will "pre-qualify" you for a mortgage before you start house-hunting. This process includes analyzing your income, assets and present debt to estimate what you may be able to afford on a house purchase. Mortgage brokers, or a lender's own mortgage counselors can also calculate the same sort of informal estimate for you.

Pre-approval makes you a strong buyer, welcomed by sellers. With most other purchasers, sellers must tie the house up on a contract while waiting to see if the would-be buyer can really obtain financing. Pre-approval will also speed up the entire mortgage procedure once you've found the house you want.