How to Measure Your Floor for Tiling
Getting the right number of floor tiles starts with an accurate measurement of your floor space. Unlike wall tiling — where you can see and feel the edges easily — floor measurements can be complicated by fitted furniture, skirting boards, alcoves, and irregular room shapes. Here is a detailed guide to measuring floors correctly in any UK home.
Start by clearing the floor as much as possible. Remove loose rugs, freestanding furniture, and any other items that obstruct the edges of the room. If you are measuring a kitchen with fitted units, you generally only need to tile the visible floor area, not underneath the cupboards. However, if you are fitting a new kitchen and tiling first, measure the entire room.
Rectangular Rooms
For a standard rectangular room, measure the length along the longest wall and the width along the shortest wall. Take your tape measure from skirting board to skirting board at floor level. Record measurements in metres to two decimal places (e.g., 3.47m rather than "about 3 and a half metres"). Multiply length by width to get the area in square metres.
L-Shaped Rooms
Many UK homes have L-shaped living rooms, especially 1930s semis and ex-council properties. The easiest way to calculate an L-shaped floor is to imagine the room as a full rectangle, then subtract the missing corner. Our calculator's L-shape mode does exactly this: enter the full rectangle dimensions, then specify the size of the cut-out. Alternatively, split the L into two rectangles, calculate each separately, and add them together.
Rooms with Bay Windows
Bay windows add a small triangular or trapezoidal area to the floor. The simplest approach is to measure the bay as a rectangle that fully encloses it (length of the bay from the wall line to the furthest point, times the total width). This slightly overestimates the area, which is safer than underestimating. The extra tiles will go towards your wastage allowance.
Dealing with Irregular Shapes and Cutting Tiles
Every floor tiling job involves some cutting, whether it is trimming tiles to fit against walls or notching around door frames and pipes. The amount of cutting — and therefore the wastage — depends largely on two factors: the laying pattern and the room complexity.
Straight grid patterns produce the least waste because cuts are straight lines parallel to the tile edges. A standard wet tile cutter or snap cutter handles these easily. Brick bond (offset by half a tile width each row) increases waste slightly because the end of each row alternates between a full tile and a half tile. Diagonal patterns require angled cuts along every wall, increasing waste by 10–15%. Herringbone is the most wasteful pattern, with every edge tile needing a precise 45-degree cut.
For pipes and other obstacles, you will need a tile scribe and nippers, or a diamond hole cutter attachment for your drill. These cuts produce small waste pieces that cannot be reused, so factor them into your wastage allowance. In a typical bathroom floor with two pipe runs, expect to waste an additional 2–3 tiles on pipe cuts alone.
Underfloor Heating and Floor Tiles
Tiles are an excellent choice for underfloor heating (UFH) systems because ceramic and porcelain are outstanding heat conductors. The tile calculation itself is identical whether or not you have UFH — the heating does not change the number of tiles needed. However, the installation method differs:
- Adhesive: Use a flexible (S1 or S2 class) tile adhesive, such as Weber Set SPF or Mapei Keraquick S1. Rigid adhesives can crack when the screed expands and contracts with heating cycles.
- Grout: Use a flexible grout for the same reason. Mapei Keracolor FF or BAL Micromax 2 are popular choices in the UK.
- Screed depth: Ensure the screed over the UFH pipes is at least 25mm thick before tiling. A self-levelling compound on top creates an ideal flat surface for large-format tiles.
- Commissioning: The UFH system must be commissioned (turned on and run through at least two heating cycles) before tiling. This pre-shrinks the screed and prevents future cracking.
Common UK Floor Tile Sizes
The table below lists the most popular floor tile sizes available from UK retailers including Topps Tiles, Wickes, B&Q, Tile Giant, and Porcelain Superstore. Prices are approximate 2026 figures and vary by material, finish, and supplier.
| Size (mm) | Tiles/m² | Price Range/m² | Best For |
|---|---|---|---|
| 300 × 300 | ~11 | £12 – £35 | Small bathrooms, en-suites |
| 330 × 330 | ~9 | £14 – £38 | Utility rooms, cloakrooms |
| 450 × 450 | ~5 | £18 – £45 | Kitchens, hallways, bathrooms |
| 500 × 500 | ~4 | £20 – £50 | Living areas, conservatories |
| 600 × 300 | ~5.4 | £18 – £48 | Versatile rectangular format |
| 600 × 600 | ~2.8 | £22 – £65 | Open-plan living, large rooms |
| 800 × 400 | ~3 | £28 – £70 | Contemporary homes |
| 900 × 450 | ~2.4 | £30 – £75 | Large kitchens |
| 1200 × 600 | ~1.4 | £35 – £90 | Luxury, open-plan spaces |
How to Lay Floor Tiles: A Quick Overview
Once you have calculated and ordered your tiles, the installation process follows these general steps. While a full tiling guide is beyond the scope of a calculator tool, understanding the process helps explain why wastage allowances matter.
- Prepare the substrate — Clean, level, and prime the floor. Self-levelling compound may be needed for uneven surfaces. Plywood overlay for timber floors.
- Find the centre — Snap chalk lines from the centre of opposite walls to find the room's centre point. This ensures a symmetrical layout with balanced cuts at the edges.
- Dry lay — Place tiles along the chalk lines without adhesive to check the layout. Adjust the starting point if the edge cuts would be less than half a tile wide — thin slivers are difficult to cut and look unprofessional.
- Apply adhesive — Spread adhesive with a notched trowel (typically 10–12mm notch for floor tiles). Work in small sections of about 1m² at a time to prevent the adhesive skinning over.
- Lay tiles with spacers — Press each tile into the adhesive with a slight twisting motion. Insert tile spacers to maintain consistent grout gaps. Check levels frequently with a spirit level or straight edge.
- Cut edge tiles — Measure and cut tiles individually for each edge — walls are rarely perfectly straight. A wet tile cutter provides the cleanest cut for porcelain and ceramic tiles.
- Grout — After 24 hours (longer for large-format tiles), apply grout using a rubber float. Wipe excess with a damp sponge before it hardens. Seal the grout after curing if recommended by the manufacturer.
Frequently Asked Questions
Break the L-shape into two rectangles. Measure the overall length and width, then measure the smaller section that makes up the "cut-out" of the L. Calculate the full rectangle area and subtract the cut-out area. Our calculator has an L-shape mode that does this automatically.
For small rooms (under 4m²), 300×300mm or 330×330mm tiles work well. They reduce the number of cuts needed and create a balanced look. Surprisingly, 600×300mm tiles laid lengthwise can also make a small room appear larger by drawing the eye along the longer dimension.
Yes. A diagonal (45-degree) pattern typically wastes 10–15% more tiles than a straight grid pattern because every tile along every wall edge needs an angled cut. Herringbone patterns waste even more — typically 15–20% extra. Our calculator adjusts the wastage figure automatically when you select a pattern.
Yes, tiles are excellent conductors of heat and are ideal for underfloor heating (UFH). Use a flexible tile adhesive (S1 or S2 rated) to accommodate thermal expansion. The tile quantity calculation is the same — underfloor heating does not change the number of tiles needed, only the adhesive type.