<prompt> Human: Just trying to see if I am missing something. Wouldnt it make more sense to calculate based on the NET, the money you actually see vs the gross which is irrelevant in real life?In my case, I make 6500 GROSS a month, or 78000 a year. My net income is 4000 though after taxes, 401k, health. Using that equation, I can afford 1820 if I use the gross amount or 1120 using the net amount. Its a huge difference.  <response>: Basically, gross places everyone on an equal scale, so to speak. Net income can be manipulated many ways. Adjust tax deduction, raising 401k contribution, voluntary deductions to other accounts which are ambiguously categorized by allotments, not to mention other miscellaneous deductions. It isnt an accurate measurement to judge one persons net income with only tax deductions, to anothers with multiple and various deductions. 