Is there any easy and quick way to figure out how much of a total mortgage one can generally afford based on how much one can afford to pay as a monthly payment? That is, if I pay X amount each month in rent, I can afford a house of Y*X value without increasing my monthly payment.

I’ve searched the web for Mortgage calculators, and while I can understand their desire for how long the mortgage will last and current interest rate (and can someone tell me how to find that out?) they also seem to require arcane information (Prime Weekly Bi-Section Flummox Rate or what have you) that I can’t fathom, let alone find.

Thanks!