Tile Calculator

What this calculator does. It works out how many tiles you need to cover a floor or wall, including a sensible waste buffer for cuts and breakages, so you can order the right number of boxes in one go.

The formula in plain English. Tiles needed = (area in m² ÷ single tile area in m²) × (1 + waste %). We always round up to a whole tile, because there's no such thing as buying half a tile, and we recommend rounding again to a whole box when you order — boxes are how tiles are sold and dye lots vary between batches.

A worked example. A 4 m × 3 m bathroom floor is 12 m². With 30 × 30 cm tiles, each tile covers 0.09 m², so the bare minimum is 12 ÷ 0.09 = 134 tiles. Add a 10% buffer for cuts and you need 148 tiles. If the boxes contain 10 tiles each, that's 15 boxes — and you'll have a couple of spare tiles left over for future repairs, which is exactly what you want.

Why this matters. Tile shopping is unforgiving. Order too few and you'll likely face a different dye lot when you go back — visible on every wall in the room for the life of the floor. Order wildly too many and you've spent £100+ on material you can't return once boxes are open. Getting the figure right also makes quoting and price-comparing dramatically easier: once you know the exact number of boxes, you can compare three suppliers in five minutes instead of guessing.

When to use it. Planning a bathroom, kitchen splashback or floor project; comparing how much a slightly bigger or smaller tile will cost overall; checking a quote from a tiler against an independent estimate; or working out whether a discounted clearance range has enough stock for your room.

When not to rely on it alone. Rooms with awkward features — bay windows, alcoves, sloping ceilings, shower niches — usually need a tiler to mark out cuts before you can be confident on quantity. Mosaic sheets and patterned tiles also need pattern-matching waste that's hard to predict generically; ask the supplier for their recommended waste percentage for that specific design.

Common mistakes. Using centimetres instead of metres for the area (the result will be 10,000 × too big), forgetting to add waste at all, and not checking the box count — tile boxes vary from 5 tiles to 20+ depending on size, so "I need 150 tiles" doesn't translate cleanly to "I need 15 boxes" without checking.