Why 15% waste is normal
Straight-lay layouts lose little to cuts; diagonals, herringbone and small rooms push waste toward 20%. Extra tiles also future-proof repairs when styles get discontinued.
Number of tiles and boxes for any floor or wall area, including cuts, breakage and pattern waste.
tiles = area × (1 + waste%) ÷ tile area in sq ft
100 sq ft with 12×12 tiles and 15% waste → 115 tiles; boxes of ten mean buying 120.
Straight-lay layouts lose little to cuts; diagonals, herringbone and small rooms push waste toward 20%. Extra tiles also future-proof repairs when styles get discontinued.
Exactly 100 without waste — each tile is one square foot; buy ~115 with the standard margin.
Cubic yards or meters of concrete needed for slabs, footings and columns — with bags count.
Gallons of paint for a room from wall dimensions, doors, windows and coat count.
Running cost of any appliance from wattage, hours used and your utility rate.
Roof squares and material bundles from footprint area and pitch, with waste factor.
Tons or cubic yards of gravel for driveways and paths, with depth and compaction allowance.
Bags or cubic yards of mulch to cover beds at the right depth.