Tile Calculator — Tiles & Boxes Needed
Work out how many tiles and boxes you need for a floor or wall from the area, tile size and a waste allowance. Metric or imperial, in your browser.
🔒 Calculated in your browser. Includes a waste allowance for cuts and breakage — increase it for diagonal or patterned layouts.
Tiles and boxes to buy
Enter the area to cover and the size of one tile, and the tool divides them to get the tile count, adds a waste allowance for cuts and breakage, and works out how many boxes you need. Tile size is entered in inches (imperial) or centimetres (metric).
Allow for waste
A 10% waste allowance is a common default for straight layouts; increase it for diagonal or patterned installs, which waste more on cuts. Buying a full extra box also gives you spares for future repairs. Everything runs in your browser.
Why the waste percentage is not padding
Every cut tile leaves an offcut, and most offcuts are unusable. A plain grid on a square room wastes least; a diagonal or herringbone layout cuts every tile at the edge and wastes most; a room with alcoves, a chimney breast or a curved threshold wastes more again. Trade practice is around 10% for a straight layout in a simple room, and 15% or more for diagonal work or an awkward shape. Large-format tiles waste more than small ones, because each ruined cut costs more area. The default here is a starting point, not a recommendation for your room.
Grout lines, boxes and the spare box
The tile size you enter is the tile, not the tile plus its grout line. On a 300 mm tile a 3 mm joint adds about 2% to the coverage, which is inside the waste allowance and is why this is not worth modelling separately. Boxes are rounded up, so a leftover part-box is normal and expected. Keep it: tiles are made in batches and the shade drifts between them, so a box bought a year later to replace a cracked tile is often visibly not the same colour.
Frequently asked questions
How many tiles do I need?
Divide the area to cover by the area of one tile, then add ~10% for cuts and breakage. The tool does this and rounds up to whole tiles and boxes.
How much waste should I add?
Around 10% for a straight layout in a simple rectangular room, 15% or more for diagonal or herringbone patterns, and more again for a room with many corners, alcoves or curves. Large tiles waste more than small ones.
Does it allow for grout lines?
Not separately. A normal joint adds a couple of percent to the coverage, which sits comfortably inside any sensible waste allowance.
Why is the box count rounded up?
Because tiles are sold by the box. The remainder is the spare stock you want anyway — replacement tiles bought later frequently come from a different batch and a different shade.