Tile Calculator — Tiles, Adhesive & Grout Estimator
Calculate exactly how many tiles you need for any floor or wall, including adhesive and grout. Enter your room dimensions, choose a tile size and layout pattern, and get a complete material list with waste factor included.
How many tiles do I need?
Divide the area by the face area of one tile, then add waste — 10% for a straight lay, 15–17% for diagonal or herringbone. A 300 × 300 mm tile covers 0.09 m²; a 12 × 12 in tile covers 1 sq ft, which makes the sum easy in either system. Always buy a spare box: tiles crack during cutting and dye lots change between orders.
How much tile adhesive do I need per m²?
It scales with tile size, because bigger tiles need a deeper notch. Tiles up to 200 mm (8 in) take about 3.5 kg/m² (0.7 lb/sq ft), up to 400 mm (16 in) about 4.5 kg/m² (0.9 lb/sq ft), and large format above that about 5.5 kg/m² (1.1 lb/sq ft). Large tiles also need back-buttering, which is extra again.
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Plan the whole job — not just this calculation
Save results to a project: budget and shopping list build themselves, and the whole plan exports as a PDF. Draw your floor plan and room sizes pre-fill the calculators.
How the tile calculator works
- 1Calculate the total area to tile (length × width in m²)
- 2Divide area by single tile area to get base tile count
- 3Apply waste factor: straight lay 10%, diagonal 17%, herringbone 15%
- 4Adhesive: multiply net area by kg/m² rate — 3.5 kg for tiles ≤200 mm (8 in), 4.5 kg up to 400 mm (16 in), 5.5 kg for large format; roughly 0.7–1.1 lb per sq ft
- 5Grout: calculated from tile perimeter, joint width, tile thickness and grout density (1.7 kg/dm³, about 106 lb/cu ft)
- 6Round up tiles to nearest whole number; round adhesive and grout up to nearest pack
Worked example
Bathroom floor: 2.4 m × 3.2 m = 7.68 m² (8 × 10½ ft, 83 sq ft). Tile size 300×300 mm — 12 × 12 in — 10 mm thick, straight lay (10% waste).
You need 94 tiles (0.09 m² each), 38 kg adhesive at 4.5 kg/m² — 84 lb, or 0.9 lb per sq ft — and ~2.9 kg (6½ lb) grout at a 3 mm (⅛ in) joint width.
Frequently asked questions
How much extra tile should I buy for waste?
For a straight lay add 10%, diagonal or herringbone patterns 15–17%. Always buy at least one spare box — tiles can crack during installation and dye lots change.
How much adhesive do I need per m²?
Standard tiles (≤200 mm, 8 in): 3.5 kg/m², about 0.7 lb per sq ft. Medium format (200–400 mm, 8–16 in): 4.5 kg/m², 0.9 lb/sq ft. Large format (>400 mm, 16 in): 5.5 kg/m², 1.1 lb/sq ft — large tiles also require back-buttering.
How do I calculate grout for tiles?
Grout quantity depends on tile size, joint width and tile thickness. Use the formula: ((L+B)÷(L×B)) × joint width × tile thickness × 1.7. Our calculator does this automatically.
How many tiles do I need for a 10 m² bathroom?
For 300×300 mm (12 × 12 in) tiles with 10% waste you need approximately 123 tiles (10 ÷ 0.09 × 1.10 = 122.2, rounded up). For 600×600 mm (24 × 24 in) tiles you need approximately 31. Use the calculator above for your exact tile size.
What tile size is best for a small bathroom?
Larger tiles (≥400 mm, or 16 in) create fewer grout lines and make small spaces feel bigger. However, large-format tiles require a very flat substrate and experienced installation.
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