Tiling a floor
Tile is already picked in the flooring calculator here. Enter the floor’s length and width (add an area for each part, or tick L-shaped), then the tile size printed on the carton, the joint you plan to use and the tile’s thickness. The result gives the tiles to buy with the waste allowance, the boxes if you enter the tiles per box, and the grout.
Tiles are counted on a module of tile plus joint: a 12 × 24 in tile with a 1/8 in joint takes up 12⅛ × 24⅛ in of floor. A straight lay begins with Daltile’s suggestion of 10% extra, and diagonal with 15%. Herringbone and chevron have no percentage at all: every tile is laid out and the cut ones counted, as the herringbone page explains. Herringbone needs rectangular tiles, and the calculator warns if you pick it with square ones.
Grout
Grout fills the joints to the depth of the tile, so the amount depends on the tile’s edges per square metre, the joint width and the tile thickness. The calculator uses the formula printed in Mapei’s Keracolor data sheet, with a density factor of 1.6, which reproduces the consumption table in Mapei’s Ultracolor Plus sheet. The two grout tables further down, in kilograms and in pounds, make it plain how fast small tiles and wide joints add up. Custom Building Products notes that a 1/8 in joint that ends up 1/32 in wider needs 25% more grout, so round up rather than down. Enter your bag size (Mapei sells Ultracolor Plus in 5 kg bags in Australia and Ultracolor Plus FA in 10 and 25 lb bags in the US) to get the number of bags.
Before you buy
Keep a few spare tiles for repairs, as Daltile suggests. For walls, switch Where to Walls, or open the wall tile page: windows, doors, the tiled height and trim are handled there, row by row.
Grout per m² by tile and joint
Kilograms of grout for one square metre, from (A + B) ÷ (A × B) × C × D × 1.6. Multiply by your floor area.
| Tile, thickness | 2 mm joint | 3 mm joint | 5 mm joint | 8 mm joint |
|---|---|---|---|---|
| 10 × 10 cm, 7 mm | 0.45 kg | 0.67 kg | 1.12 kg | 1.79 kg |
| 20 × 20 cm, 8 mm | 0.26 kg | 0.38 kg | 0.64 kg | 1.02 kg |
| 30 × 30 cm, 9 mm | 0.19 kg | 0.29 kg | 0.48 kg | 0.77 kg |
| 60 × 30 cm, 9 mm | 0.14 kg | 0.22 kg | 0.36 kg | 0.58 kg |
| 60 × 60 cm, 10 mm | 0.11 kg | 0.16 kg | 0.27 kg | 0.43 kg |
| 120 × 60 cm, 10 mm | 0.08 kg | 0.12 kg | 0.20 kg | 0.32 kg |
Grout per 100 sq ft by tile and joint
| Tile, thickness | 1/16 in joint | 1/8 in joint | 3/16 in joint | 1/4 in joint |
|---|---|---|---|---|
| 4 × 4 in, 1/4 in | 6.5 lb | 13.0 lb | 19.5 lb | 26.0 lb |
| 6 × 6 in, 5/16 in | 5.4 lb | 10.8 lb | 16.3 lb | 21.7 lb |
| 12 × 12 in, 3/8 in | 3.3 lb | 6.5 lb | 9.8 lb | 13.0 lb |
| 12 × 24 in, 3/8 in | 2.4 lb | 4.9 lb | 7.3 lb | 9.8 lb |
| 24 × 24 in, 3/8 in | 1.6 lb | 3.3 lb | 4.9 lb | 6.5 lb |
| 6 × 36 in, 3/8 in | 3.8 lb | 7.6 lb | 11.4 lb | 15.2 lb |
Sources, checked September 2026: Mapei, Keracolor GG data sheet (consumption formula) and Ultracolor Plus data sheet (consumption table, 5 kg bags); Daltile, FAQs; Custom Building Products, TB89; Armstrong Flooring, Estimating. Real use varies with the tile's edges and how clean the joints are left.