Tile and grout calculator
How many tiles, how many boxes and how much grout for a floor or wall.
How it works
Tiles: area ÷ (tile length + joint) × (tile width + joint), plus waste for cuts and breakages. Grout comes straight from the shape of the joints. For a tile A × B with joint width J and depth T (all in mm), each square metre holds (A + B) ÷ (A × B) × J × T litres of grout. Multiply by the grout's density, about 1.8 kg per litre for cement grout, and add 10% for what's left on the float and sponge.
Worked examples
A 3 × 2.5 m bathroom floor in 300 × 600 mm tiles, 9 mm thick, with 3 mm joints: 46 tiles including 10% waste, and 2 kg of grout (0.135 L per m²).
An 8 × 10 ft floor in 12 × 12 in tiles with ⅛ in joints: 87 tiles and about 6.4 lb of grout, so one 25 lb bag.
Small tiles use much more grout
Halve the tile size and you double the length of joint per square metre. Mosaics and small wall tiles can need several times the grout of large floor tiles, and wider joints use proportionally more. That's why grout bags give coverage as a chart, not a single figure. If your bag's chart differs from our estimate, trust the bag.
How much spare tile?
10% covers cuts in a simple rectangular room laid straight. Allow 15% for diagonal layouts, rooms with many corners, or large-format tiles, and keep a few spare tiles for future repairs.
Common questions
How many tiles do I need per square metre?
For 300 × 300 mm tiles with 3 mm joints, about 10.9 per m²; for 600 × 600 mm, about 2.7. Add 10% for cuts.
How much grout do I need?
For 300 × 300 mm floor tiles, 8 mm thick with 3 mm joints, about 0.3 kg per m². Smaller tiles and wider joints need more: use the calculator with your sizes.
Reviewed by Alex Rowan, Editor. Last reviewed . How we calculate · Report a problem