First Time Home Buyer Classes In Houston What Size Mortgage Can We Afford How To Determine What Mortgage You Can Afford Buying A house affordability calculator mortgage affordability calculator – How much mortgage can you. – Use the Money Advice service mortgage affordability calculator to find out how much mortgage you can afford to borrow for your new house. Skip to main content Accessibility Statement.. buying a home and choosing the right mortgage. Homes & Mortgages.You can do a lot of research on your own, but you need the help of an expert when it comes to actually finding and securing your perfect home. An experienced real estate agent can help you figure out how much house you can afford and what kind of homes you can expect to find, considering your market and price range.First, the borrower should know what the lender believes the borrower can afford and what size of a mortgage the lender is willing to give. Formulas are used to.