Waist to Height Ratio
The measure BMI structurally cannot give you.
Health & Home
Tile Calculator
Tile count, boxes, adhesive and grout with waste.
What it does. Tile count is area divided by the area of one tile, plus waste for cuts and breakage. Ten percent is the usual minimum; large-format tiles, diagonal layouts and rooms with many cuts need more, and grout line width slightly reduces the tile count on small tiles.
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How to use Tile Calculator
- Enter the area to tile and the tile size.
- Set waste for the layout and tile format.
- Read tiles, boxes, adhesive and grout.
Why the count is not just area divided by tile
Grout lines occupy real space. With 3mm joints and small mosaic tiles that adds up measurably; with 2mm joints and 600mm tiles it is negligible.
Cuts are the bigger factor. Every tile meeting a wall, a doorway or a fitting is cut, and the offcut is usually unusable.
This is why a bathroom uses proportionally more tile than a hall of the same area: it has more edges, more obstacles and more cuts per square metre.
Waste and breakage
| Situation | Add |
|---|---|
| Simple wall, straight lay | 10% |
| Floor with cuts around fittings | 12–15% |
| Diagonal layout | 15% |
| Large-format (600mm+) | 15% — breakage risk |
| Patterned tile needing alignment | 15–20% |
| Natural stone | 15–20% — shade sorting |
Large formats justify a higher factor for a specific reason: a big tile is far easier to break while cutting or handling, and one broken 600mm tile is worth several broken 150mm ones.
Adhesive and grout
Adhesive use depends mostly on the trowel notch, which depends on the tile size. Small wall tiles use roughly 3 to 4 kg per square metre; large-format floor tiles with a bigger notch use 5 to 8.
Grout depends on joint width, joint depth and tile size, so a mosaic uses several times the grout of a large-format floor at the same joint width.
Uneven walls change the adhesive number more than anything else. Levelling a bowed wall with adhesive can double the quantity, which is a reason to check with a straight edge before buying.
Frequently asked questions
How many extra tiles should I buy?
Ten percent minimum for a simple straight lay, 15% for diagonal layouts, large formats or natural stone. Keep a few beyond that — a cracked tile years later needs the same batch.
Why does a bathroom use more tile than a hall of the same size?
More edges, obstacles and fittings, so more cut tiles per square metre — and most offcuts are unusable.
How much adhesive do I need?
Roughly 3 to 4 kg per square metre for small wall tiles, 5 to 8 for large-format floors with a bigger trowel notch. Uneven walls can double it, so check with a straight edge first.
Do grout lines change the tile count?
Noticeably with small tiles and 3mm joints; negligibly with 600mm tiles and 2mm joints. This tool accounts for the joint width you enter.
Why do large tiles need more waste allowance?
They break more easily while cutting and handling, and one broken 600mm tile costs as much as several small ones.