Question: how do you calculate how much you can afford for a mortgage?
Answer: Step 1 - Your desired living situation. Are you looking to buy or to rent? Buy. ... 
Step 2 - Your financial information. Annual household income (before taxes)* Down Payment* Mortgage interest rate* ... 
Step 3 - Your monthly expenses. On average, how much money do you spend each month (excluding housing expenses)? $0.