Tile Calculator
Enter the room and tile sizes. The calculator adds the joint width, subtracts openings and includes an allowance for cuts.
How the number of tiles is calculated
The tile area is taken with the joint included, otherwise a large room ends up one pack short. The formula: tiles = area × (1 + waste) ÷ ((length + joint) × (width + joint)).
Worked example
A bathroom floor 1.7 × 2.5 m is 4.25 m². With 300 × 600 mm tiles and a 2 mm joint, one tile covers 0.302 × 0.602 = 0.182 m². Adding 10% waste: 4.675 ÷ 0.182 = 26 tiles, which is 3 packs of 9.
How much to allow for cutting
| Layout | Allowance | When |
|---|---|---|
| Simple room | 5% | Rectangular room, plain tile |
| Standard | 10% | Openings, niches, sanitary ware |
| Diagonal | 15% | 45° layout or a complex pattern |
| Large format | 15–20% | Tiles from 600 × 1200 mm: breakage costs more |
Two mistakes that cost money
- Buying the exact number. Tiles from different batches vary in shade and calibre, and matching the same batch a month later is usually impossible.
- Counting walls and floor together. Formats and waste differ, and walls also have doors and windows to subtract.
Adhesive and grout
Adhesive use depends on the trowel notch and how flat the substrate is: roughly 3–5 kg/m² for tiles up to 30 × 30 cm and 5–8 kg/m² for large formats. The figure on the bag is honest only for a flat substrate. Grout use grows with wider joints and thicker tiles.
Construction Material Calculators
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