Flooring & Tile
Tile Calculator
Enter your floor or wall dimensions in metres and your tile size in millimetres to get the tile and box count to buy, with grout joints and wastage included.
Formula tested · Local units · No sign-up
Project inputs
Enter measurements
Use your preferred units. Results update automatically.
Show the calculation methodFormula, conversions, rounding, and assumptions+
Each tile occupies its own size plus one grout joint: a 600 × 300 mm tile with a 3 mm joint takes up 603 × 303 mm = 0.1827 m². The area is divided by that footprint to get the exact tile count.
A wastage allowance is added for cuts and breakage — 10% for a straight lay, 15% for diagonal patterns or rooms with many cuts — and the result is rounded up to a whole tile, then to whole boxes when you enter the tiles-per-box figure.
Real-world example
Worked example: 4 m × 3 m kitchen floor, 600 × 300 mm tiles, 3 mm joints
- Area: 4 × 3 = 12 m².
- Tile footprint: 0.603 × 0.303 = 0.1827 m².
- Exact count: 12 ÷ 0.1827 = 65.68 tiles.
- Add 10% wastage: 65.68 × 1.10 = 72.25 → round up to 73 tiles.
- Boxes of 10: 73 ÷ 10 = 7.3 → round up to 8 boxes.
Buy 8 boxes (80 tiles). At an example price of £20 per box plus 20% VAT, that's £160.00 + £32.00 = £192.00.
Before you start
How to measure
- Measure the room in metres; for walls, measure the height you're tiling to (half-height tiling is common in bathrooms) rather than full wall height.
- Tile sizes are printed in millimetres on UK boxes — take the exact size and tiles-per-box from the label rather than the nominal name.
- Grout joints of 2–5 mm are typical; 3 mm suits most walls and floors, while rectified porcelain can go tighter — match what your tiler plans.
Local guidance
Notes for United Kingdom
- UK tiles are sized in millimetres — 300 × 300, 600 × 300, 600 × 600 floor formats and 200 × 100 metro wall tiles are common — and sold by the box with m² coverage on the label.
- Many UK retailers price tiles per m² but sell whole boxes; this calculator counts boxes from the tiles-per-box figure so you buy what the shelf actually holds.
- VAT at the standard 20% rate applies; retail prices normally include it, trade-counter prices often don't — check before comparing.
Quick reference
Common UK tile sizes
| Format | Size | Typical use |
|---|---|---|
| Square floor | 300 × 300 mm | Bathrooms, utility rooms |
| Rectangular floor | 600 × 300 mm | Kitchens, hallways |
| Large format | 600 × 600 mm | Open-plan floors |
| Metro wall | 200 × 100 mm | Splashbacks, bathroom walls |
Common formats for planning — actual sizes and tiles per box are on the box label.
Good to know
Common mistakes to avoid
- Entering tile size in centimetres into a millimetre field — a 600 mm tile typed as 60 gives a wildly wrong count.
- Forgetting the grout joint on large floors, or the wastage allowance on small rooms where nearly every edge row is cut.
- Topping up later from a different batch — shade varies between batches, so order the full quantity at once.
- Comparing a per-m² price against a per-box price without converting.
Need help?
Frequently asked questions
How many 600 × 600 tiles do I need for 10 m²?
With a 3 mm joint each tile occupies 0.603 × 0.603 = 0.3636 m², so 10 ÷ 0.3636 = 27.5 tiles. Adding 10% wastage gives 30.3, so buy 31 tiles.
How many 600 × 300 mm tiles per square metre?
With a 3 mm grout joint, each tile occupies 0.1827 m², so about 5.5 tiles per m² before wastage — call it 6 per m² once a 10% allowance is added.
Is VAT included in the estimate?
Only if you include it. Enter your box price and 20% VAT if the price was quoted ex-VAT (common at trade counters); enter the shelf price and 0% if VAT is already in it.
Keep planning
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About this calculator
- Written by:
- BuildMeasure Editorial Team
- Technically reviewed by:
- Pending independent technical reviewer (formula unit-tested; see methodology)
- Last reviewed:
- 2026-07-16
- Formula version:
- 1.0.0
- Region reviewed for:
- United Kingdom
- Spotted an error?
- Report a correction
Methodology
- The area to tile comes either from length × width or from a directly entered area. All arithmetic runs internally in SI units (metres and m²); regional units (inches, mm, ft²) are converted exactly on the way in and out.
- Each tile's effective footprint is (tile length + grout gap) × (tile width + grout gap) — the grout joint is counted once per tile, which is how a repeating grid actually consumes floor area.
- Tile count = area ÷ footprint, multiplied by (1 + wastage %), then rounded UP to a whole tile. When you enter tiles per box, boxes = tile count ÷ tiles per box, rounded UP to a whole box.
- The cost estimate multiplies boxes (or tiles, when no box size is given) by the price you enter, then applies the tax rate you enter. No prices are built in.
- The formula is covered by automated unit tests, including hand-calculated worked examples, and is versioned (see formula version on this page).
Sources & standards
- Unit definitions: Metric units throughout; tile sizes in mm, areas in m².
- Wastage allowances: 10% straight lay / 15% diagonal are standard planning allowances; confirm with your tiler.
This tool provides a material estimate for planning purposes only. It is not a quotation, and it does not account for layout pattern, substrate preparation, adhesive or grout quantities. Confirm quantities, box coverage and batch numbers with your tile supplier before ordering.