Creating a tile ceiling? This handy calculator will tell you how much supplies to order, and how to cut the border tiles. Also, working under the assumption that you need 100 feet of furring for every 100 sq feet of area, and 1.75 lbs of staples for every 100 square feet of furring, it will tell you how much furring you need too (optional).

The width border tiles are the tiles on opposite sides of the room where you measured the "width." The length border tiles are the tiles on opposite sides of the room from the wall you measured as the "length."

Easy, quick and effective, you should try it out now!