Tile Calculator
Find how many tiles you need for a floor or wall from the area, the tile size and a waste allowance.
How it works
tiles = ceil(area × (1 + waste%) ÷ tile area) · tile area (sq ft) = (length ÷ 12) × (width ÷ 12)
Convert the tile size from inches to feet so it matches the area, divide the area by one tile’s coverage, add the waste allowance, and round up. Ten percent is standard; add more for large-format tiles (fewer, bigger cuts waste more), diagonal layouts, and rooms with many edges. Buy an extra box beyond that for repairs — matching a discontinued tile years later is nearly impossible.
Worked example
An 80 sq ft floor in 12 × 12 in tiles: each tile covers 1 sq ft, so 80 × 1.10 = 88 tiles. At 10 tiles per box that is 9 boxes.
Frequently asked questions
How much waste for tile?
Ten percent for a standard straight or grid layout, 15% for diagonal and herringbone, and up to 20% for large-format tiles or rooms with many cuts. Cutting waste and the occasional cracked tile add up fast.
Should I keep spare tiles?
Always keep at least a few from the same production lot. Tile glazes shift between batches, so a repair tile bought later — if it is even still made — will rarely match the floor.
Does grout width change the count?
Slightly. Wider grout joints mean fewer tiles per area, but the effect is small next to the waste allowance, so most estimators ignore it and let the 10% absorb it.
Related calculators
Estimates only — add for waste and confirm against local building codes and supplier specs.