I’m thinking about finishing off part of my basement for a gameroom, and I’d like to be able to use a pool table down there. I’d probably get an 8 foot (44"x88") table, possibly a 7 foot (38"x76") table (whatever size they typically use in bars). The room I’d have would be about 140 inches (11 foot, 8 inches) across after the room is finished. Is this wide enough? The length isn’t a problem.
As long as you have 5’ or more room on all sides of the table you’re fine.
take the length of a pool cue (perhaps a shortened one, if needed), and add that length all around the playing surface of the table, so that if you’re playing the cue ball off the bank, you don’t need to jackup the butt of the cue, or take it apart, to make the shot…
not really any more complicated than that… 
Glenoled
I love the Internet.
Here’s a chart showing what size room you need for what size pool table and what size cues you’re going to be using.
http://www.patiostore.com/roomchart.html