Theres 2.77 s/f per 20x20 so a bare minimum of 324.9 tile or 325 tile..

And theres 1.77 s/f per 16x16 or a minimum of 508.4 tile or 509..

You ll need a 10% scrap factor (90 s/f) in larger tile so at least 360 ( 20x20) and 560 (16x16) tiles.

A few factors that may incress or decress this is you may have to buy whole boxes or if this is a wide open area or chopped up with other rooms, closets, hall ways etc.. GL

http://www.toppstiles.co.uk/tile-calcula...