To find out exactly how much money your mortgage can be lenders will look at several factors.  These factors include employment status, personal assets, credit scores and any late payments you may have had over the last few years.  Once again this is not an exact science, but it is a method that has proven to work, for the most part.  Something I would recommend all first time home owners to do is to check their credit score before getting a pre mortgage approval.  There may be some mistakes on your credit score that could drop the score over 100 points.  It is better to find out about these and try to resolve them rather than the lender finding out.

Overall, you will not get to determine how much of a mortgage you will get.  What you can do is to make smart financial decisions and keep your credit history clean.  This will enable you to get a mortgage more to your liking.  If you have a credit score over 750, a stable source of income and some assets to your name, it is likely you will get a reasonable sized mortgage at a low rate to buy the home of your dreams.