Downloading office upgrade

[Stree]

is there a max number of computers I can install one purchase of the office
upgrade on? I have 4 pc's i'd like to use it on...

 

[Bob I]

Depends entirely on the version and use intended. But with 4 at a
minimum you will need at least 2 licenses and maybe as many as 4.
Perhaps you will gain by reviewing the Office site?

http://office.microsoft.com/en-us/suites/FX101678741033.aspx