How do I calculate how many tiles I need?

Measure the length and width of the area in metres and multiply them to get the square metres. Subtract any obstacles, then add 10% for cuts and wastage. Divide the final area by the coverage of one tile (in m²) and round up.

How much extra tile should I allow for wastage?

For most rooms, allow 10% extra. For diagonal patterns, large-format tiles, or complex layouts, 12–15% is safer.

How do I measure an irregularly shaped room?

Divide the space into smaller rectangles. Calculate each area (length × width) and add them together. Subtract the areas of any obstacles you will not tile.

Should I subtract fixtures like baths and cabinets?

Yes. Measure each obstacle (length × width), convert to m² and subtract from the total area before adding your wastage allowance.

How do I convert from tiles to boxes?

Check the box coverage or number of tiles per box on the product page. After calculating tiles needed, divide by tiles per box and round up to the next whole box.

How to Calculate Square Metres of a Room for Tiling

Posted by As'ad Mansoor on 18th May 2024

How to Calculate Tiles Needed for Your Room (Free Tile Calculator)

Planning to tile a room? Before buying, work out the correct quantity so you avoid delays or waste. This guide shows you exactly how to measure any space and calculate the square metres, plus a free tile calculator for popular UK sizes.

Step 1: Gather Your Tools

Have these at hand:

Tape measure or laser distance measurer
Notes app or pen and paper
Calculator

Step 2: Measure the Room

Rectangular or Square Rooms

Measure the length and width in metres.
Multiply them: Area = Length × Width.

Example: 5m × 4m = 20m²

Irregular Rooms

Divide the room into smaller rectangles. Calculate each area, then add them together.

Example: Section A = 3m × 2m = 6m²; Section B = 4m × 3m = 12m². Total = 18m²

Step 3: Account for Obstacles

Subtract fixed features that will not be tiled (for example, baths, built-in cabinets).

Example: Obstacle = 1m × 0.5m = 0.5m²; Adjusted total = 18m² − 0.5m² = 17.5m²

Step 4: Add Extra for Waste

Allow for cuts and spares. For most jobs, add 10%. For diagonal layouts or complex spaces, consider 12–15%.

Example: 17.5m² + 10% = 19.25m²

Step 5: Round Up to Boxes

Tiles are sold by the box. Round up to the next full box to ensure full coverage.

Free Tile Calculator

Choose a popular tile size or enter a custom size. Add obstacles, adjust wastage, and optionally calculate boxes.

Tile Size Mode

Select tile size (cm)Selection automatically sets per-tile coverage (m²).

Per tile coverage (m²)

Room length (m)

Room width (m)

Obstacles total (m²) (optional)

Wastage (%)

Tiles per box (optional)

Final Thoughts

By following these steps and using the calculator above, you will know exactly how many tiles to purchase. For peace of mind, round up to full boxes and keep a few spares for future repairs.