How to use the tile calculator
- Measure the floor or wall area to tile. For a wall, use its width and the height you will tile to.
- Enter the tile size and the grout joint you plan to use, then the number of tiles in a box.
- Choose a waste allowance: 10% for straight layouts, 15% for diagonal or herringbone, and more for small rooms full of cuts.
- Open More options to set the tile thickness, the grout bag size and how much area one bag of adhesive covers with your trowel.
- Add prices to see the cost of tiles, grout and adhesive.
How the estimate is worked out
Grout (kg/m²) = (A + B) ÷ (A × B) × joint width × joint depth × 1.6
Adhesive bags = area × (1 + waste %) ÷ area per bag
The grout formula is the one many grout makers print, with A and B the tile sides, all in millimetres, and joint depth taken as the tile thickness. The factor 1.6 is a typical density for cement grout in kilograms per litre; epoxy and other grouts differ, so check the bag.
Worked example
A 10 × 8 ft floor tiled with 12 × 12 in tiles, a 1/8 in joint, 10 tiles per box, 10% waste and tiles at $4 per square foot:
- Area: 10 × 8 = 80 sq ft.
- Each tile with its joint covers 12.125 × 12.125 in = 1.0209 sq ft.
- Tiles: 80 × 1.10 ÷ 1.0209 = 86.2, rounded up to 87 tiles, which means 90 tiles (9 boxes).
- Grout for 3/8 in thick tiles: 5.7 lb (1 × 10 lb bag). Adhesive at 95 sq ft a bag: 1 bag.
- Tiles, grout and adhesive together: $400.00.
Tips and common mistakes
- Buy from one lot. Tiles vary in shade and sometimes in size between production runs. Check that every box shows the same shade or caliber code.
- Plan the layout from the centre. Dry-lay a row each way so cut tiles at the walls are at least half a tile wide.
- Match the grout to the joint. Unsanded grout suits narrow joints; sanded grout suits joints of about 1/8 in (3 mm) and wider.
- Waterproof wet areas properly. Showers need a waterproofing membrane behind the tiles, and grout alone does not keep water out.
US, UK and Canada differences
North American tile is sold by the square foot and the box, with thinset mortar in 50 lb bags and grout in bags of a few pounds up to 25 lb. Joints are described in fractions of an inch, such as 1/16 or 1/8 in. In the UK, tile prices are per square metre, adhesive comes in 20 kg bags and grout in smaller bags of a few kilograms. Canadian products often show both sets of units; metric mode suits them well.
Metric units and other countries
In metric mode, tile sizes are in centimetres and joints in millimetres, so a 600 × 600 mm tile is entered as 60 × 60 cm. Large porcelain tiles such as 60 × 120 cm are common in South Asia and the Gulf; they need a flat floor, back-buttering and a bigger waste allowance for breakage. Type your local price per square metre and per bag.