How to Calculate Tiles Needed

Measuring Your Space

For a simple rectangular room, measure the length and width in metres. Round up to the nearest 10cm.

Example: bathroom floor 2.8m × 2.2m = 6.16 m²

Irregular Shapes

Break complex rooms into rectangles. An L-shaped kitchen becomes two rectangles: add their areas together.

For curved areas or bay windows, measure the widest points and add extra wastage (15-20%).

Tile Sizes and Coverage

UK tiles come in standard sizes. Work out area per tile:

Worked Example

Bathroom floor: 2.8m × 2.2m = 6.16 m²
Tile choice: 300×300mm porcelain
Calculation: 6.16 m² ÷ 0.09 m² = 68.4 tiles
With 10% wastage: 68.4 × 1.1 = 75.2 → round to 76 tiles

Standard box size: 300×300mm typically come 11 tiles per box
Boxes needed: 76 ÷ 11 = 6.9 → buy 7 boxes

Wastage Allowances

Straight Lay (10%)

Tiles laid square to the room. Minimal cutting needed except at edges. Standard 10% wastage covers:

• Edge cuts around perimeter
• Breakages during cutting
• A few spare tiles for future repairs

Diagonal Lay (15-20%)

Tiles at 45 degrees to walls look great but waste more material. Every edge tile needs cutting at an angle, and corner offcuts can't be reused.

Pattern Layouts (15-20%)

Herringbone, chevron, or decorative patterns with contrasting tiles need careful planning. Pattern repeats create offcuts.

Small or Awkward Rooms (15%)

Bathrooms with toilets, pedestals, and pipework need more cuts. Add extra wastage.

Boxes Per Pack

Tiles are sold in boxes (sometimes called packs). Standard quantities:

• 600×600mm: 4 tiles per box (1.44 m² coverage)
• 450×450mm: 6 tiles per box (1.22 m²)
• 300×300mm: 11 tiles per box (0.99 m²)
• 250×400mm: 12 tiles per box (1.20 m²)

Always check manufacturer specs as this varies.

Wall Tiles

Same method applies. Measure wall height × width for each wall you're tiling.

Subtract large fixtures (shower screens, mirrors) but don't bother subtracting small fittings like soap dishes.

Wall tiles often come in smaller sizes (200×250mm, 150×150mm) with more per box. Check the label.

Half-Height Tiling

For tiling halfway up a wall (common in bathrooms), measure wall length × height to tile line (usually 1.2m from floor).

Grout and Spacers

Our calculator focuses on tiles, but don't forget:

• Grout: ~1 kg per m² for 3mm joints, ~1.5 kg for 5mm joints
• Tile spacers: One pack (100-200 spacers) per 5-6 m²
• Adhesive: 3-4 kg per m² for walls, 5-6 kg per m² for floors

Always Buy Extra

Order at least one extra box beyond your calculation. Reasons:

• Future repairs (cracked tiles, stains)
• Batch matching (tiles from different batches can vary in shade)
• Mistakes happen, especially for DIY first-timers

Unopened boxes can often be returned, but trying to match a discontinued tile two years later is impossible.