How much tile do I need?

Measure the area in feet and multiply length by width to get square feet. Add 10% for cuts, or 15% for patterns and diagonal layouts.

Mosaics are sold by the sheet, and each sheet covers 1 sq ft. Large tiles such as 18x18 and 12x24 are sold by the piece: divide your area by the tile size (2.25 or 2 sq ft) and round up. Trim is sold by the piece; most pieces are 12 in long, so count one piece per linear foot plus a few spares.