Buying exactly the right number of tiles for a bathroom sounds appealing, but almost always creates problems: a tile breaks during installation, the cuts generate more offcuts than expected, or six months later a damaged tile needs replacing. By then the batch is long sold out. The tile calculator works out the number of tiles you need including a realistic wastage allowance, and also tells you how many packs to buy – because tiles are sold in packs, not individually.
Step by Step: How to Use the Tile Calculator
- Enter the area: Measure the surface to be tiled in square meters. For a bathroom: add up all wall surfaces and deduct windows and doors.
- Enter tile size: Enter the width and length of the tile, e.g. 30 × 60 cm. The calculator works out the tile area: 0.30 × 0.60 = 0.18 m².
- Allow for grout joints: Grout takes up space. Standard: 2–3 mm for wall tiles, 3–5 mm for floor tiles. The calculator adds the joint width to the effective tile size.
- Choose a wastage percentage: For straight-set layouts: 10%. For diagonal or herringbone patterns: 15–20%.
- Enter pack size: Enter how many tiles are in a pack. The result shows the number of tiles and packs needed.
Practical Examples
Example 1 – 90 × 90 cm shower enclosure: 3 walls, each 90 cm wide and 210 cm high = 3 × 0.9 × 2.1 = 5.67 m². Tiles 20 × 60 cm (0.12 m²). Base requirement: 5.67 ÷ 0.12 = 47.25 tiles. With 10% wastage: 52 tiles. At 8 tiles per pack: 7 packs (= 56 tiles).
Example 2 – Living room floor laid diagonally: Area 25 m², tiles 60 × 60 cm (0.36 m²), diagonal cuts = 15% wastage. Base requirement: 25 ÷ 0.36 = 69.4. With 15%: 80 tiles. At 3 tiles per pack (heavy): 27 packs.
Example 3 – Kitchen splashback in mosaic: Area 3.0 m × 0.6 m = 1.8 m², mosaic tiles 30 × 30 cm (= 0.09 m²). Base requirement: 1.8 ÷ 0.09 = 20 tiles. With 15% wastage for the pattern: 23 tiles. Buy 2 packs of 12 = 24 tiles.
Tile Calculator: Quantity + Wastage
Calculation: (area / tile area) × 1.1 (10% wastage) = tiles required. Important: account for grout width! Recommendation: always buy 10–15% extra.
Frequently Asked Questions (FAQ)
- How do I calculate wastage for angled cuts?
- At corners, recesses and pipe penetrations, tiles have to be cut to shape. The off-cut is often too small to reuse elsewhere and goes to waste. For simple rectangular rooms, 10% wastage is sufficient. Allow 1–2 extra tiles for each corner with an angle cut or recess.
- What is the difference between net and gross area when buying tiles?
- The net area is the actual surface to be tiled (minus doors, windows, bath). The gross area additionally accounts for wastage. Always buy based on the gross area (net + wastage + reserve). The difference between net and gross can be 20–30% in small, irregular rooms.
- When should I buy extra reserve tiles?
- Always – even if the calculator gives you an exact figure. Buy at least one pack more than calculated. Tiles from the same batch (same production run, same appearance) are often unavailable a few months later. A reserve for future repairs is far cheaper than re-tiling a whole wall.
