How to measure a room for tiling

A practical guide for homeowners and DIY tilers

Why accurate measurements matter

Every tiling project starts with a tape measure. Get the room dimensions wrong and you'll either buy too few tiles — causing delays and mismatched batches — or too many, wasting money. Worse, inaccurate measurements lead to poor tile layouts with ugly thin cuts at the edges.

Professional tilers measure twice and order once. This guide shows you how to do the same, whether your room is a simple rectangle or an awkward L-shape.

What you'll need

• A tape measure (5m or longer, metric and imperial)
• A notepad or your phone's notes app
• A pencil for marking reference points on the floor
• A laser distance measurer (optional but highly recommended for rooms over 3 metres)

Measuring a rectangular room

Most bathrooms, kitchens, and utility rooms are roughly rectangular. Measure the length and width at their widest points — walls are rarely perfectly parallel, so take measurements at both ends and use the larger number.

1. Measure the width of the room from wall to wall. Record in centimetres (e.g. 285 cm).
2. Measure the length from wall to wall. Record in centimetres (e.g. 340 cm).
3. Check for square by measuring the diagonal — the two diagonals should be equal. If they differ by more than 1 cm, note which corner is out of square.

Measuring an L-shaped room

An L-shaped room is simply two rectangles joined together. The key is to break the shape into its component sides and measure each one.

Walk around the room perimeter and measure each wall segment in order — right, up, left, down — recording as you go. For example, a simple L-shape might be: 500 cm right, 200 cm up, 200 cm left, 100 cm down, 300 cm left, 100 cm down.

The Tile Cut Plan's Pro mode accepts exactly this format — just type the side lengths separated by spaces and it builds the room shape automatically.

Measuring around obstacles

Toilets, basin pedestals, and kitchen islands don't reduce your tile order — you still need tiles for underneath fitted furniture and around plumbing. Measure the full room dimensions as if the obstacles weren't there. The cutting waste allowance (typically 5-10%) covers the extra cuts needed around obstacles.

Common mistakes

• Measuring in the wrong unit. Mixing centimetres and metres in the same measurement causes errors. Pick one unit and stick with it.
• Forgetting door thresholds. Tiles often extend into the doorway — measure to the centre of the door frame, not the wall face.
• Ignoring out-of-square walls. If walls aren't parallel, the tile cuts on one side will be wider than the other. A good layout plan accounts for this.
• Rounding too aggressively. "About 3 metres" could be 285 cm or 315 cm — a 10% difference that changes your tile count significantly.

From measurements to tile count

Once you have your room dimensions, you need to calculate how many tiles to buy. This depends on tile size, grout gap width, and the layout pattern you choose. A straight layout wastes less than a diagonal one, and larger tiles mean fewer cuts but more waste per cut.

Rather than doing the maths by hand, enter your measurements into a tile calculator that accounts for all these variables — including cut waste at each wall edge.