Tile Calculator
in
in
in
in
in
10%
Tiles Needed110
Boxes (12/box)10
Total Area14,400 sq in
This tile calculator counts how many tiles you need to cover a floor or wall, accounting for the grout gap between tiles and a waste allowance for cuts and breakage. It works in inches: you give the area dimensions and the tile dimensions, and it tiles the surface row by row, rounding up so partial tiles still require a whole tile. It then groups the tiles into boxes of twelve.
Formula
tiles = ⌈⌈L ÷ (t_L + gap)⌉ × ⌈W ÷ (t_W + gap)⌉ × (1 + waste%)⌉ ; boxes = ⌈tiles ÷ 12⌉
- L, W
- Area length and width in inches
- t_L, t_W
- Tile length and width in inches
- gap
- Grout gap added to each tile dimension, in inches
- waste%
- Extra allowance as a fraction (e.g. 0.10 for 10%)
- boxes
- Number of boxes at 12 tiles per box, rounded up
How it works
- Enter the area length and width in inches, and the tile length and width in inches.
- Enter the grout gap in inches (added to each tile dimension) and a waste percentage for cuts and spares.
- The calculator divides each area dimension by the tile-plus-gap size and rounds up to whole tiles per row and column, multiplies for the base count, applies the waste factor, rounds up again, and finally divides by 12 tiles per box.
Worked example
A 120 in by 96 in floor with 12 in by 12 in tiles, a 0.25 in grout gap, and 10% waste.
- Effective tile size: 12 + 0.25 = 12.25 in each way.
- Tiles along length: ⌈120 ÷ 12.25⌉ = ⌈9.80⌉ = 10. Tiles along width: ⌈96 ÷ 12.25⌉ = ⌈7.84⌉ = 8.
- Base tiles: 10 × 8 = 80. With waste: 80 × 1.10 = 88, rounded up to 88.
- Boxes: ⌈88 ÷ 12⌉ = 8.
88 tiles, which is 8 boxes.
Frequently asked questions
- Why does the grout gap change the tile count?
- The gap effectively makes each tile occupy slightly more space. The calculator adds the gap to both tile dimensions before dividing into the area, so wider grout lines mean each tile covers more surface and you may need fewer tiles.
- How much waste should I add?
- A 10% allowance is typical for straightforward layouts, covering edge cuts and the occasional cracked tile. Diagonal patterns, many obstacles, or fragile tiles can justify 15% or more, and keeping spares for future repairs is wise.
- Why does the calculator round up at each row?
- A partial tile at the edge of a row still requires cutting from a whole tile, so the count rounds up per row and column. This reflects real installation rather than treating fractional tiles as available.
- How many tiles are in a box?
- This calculator assumes 12 tiles per box and divides the total by 12, rounding up. Real boxes vary by product and tile size, so check the manufacturer's box quantity and adjust your order accordingly.