What it does
This tile calculator counts the tiles and boxes you need for a floor or a wall, adds a share for cuts and breakages, and estimates the grout. The Planks tab does the same for laminate, vinyl or wood flooring sold by area per box.
If the walls are being painted or papered at the same time, the paint calculator and the wallpaper calculator work out the rest of the room.
How to use it
- Pick Tiles or Planks, and metric or imperial (changing units loads the example in those units).
- Type the length and width of the area. For an L-shaped room add a second rectangle; to leave out a bath or a kitchen unit, add one set to Take away.
- Type the tile size and choose the layout.
- Type what a box holds, from the label.
What each setting does
- Layout: straight lays use 10% waste; diagonal and herringbone use 15% because more tiles are cut. Choosing a layout fills in the waste box.
- Waste and cuts: the extra share added before rounding up. Raise it for small rooms or fragile tiles.
- Box sold by: tiles per box, or area per box. Boxes always round up.
- Grout gap and tile thickness: the joint width and depth. Small tiles need more grout.
- Grout per litre of joint: 1.6 kg is a rule of thumb for cement grout; the bag gives the real figure.
The count uses the tile size alone and leaves out the joints, which makes it a touch generous.
Worked example
A floor 3 m by 4 m is 12 m². A 30 × 30 cm tile covers 0.09 m², so the floor takes 133.3 tiles. Add 10%: 133.3 × 1.1 = 146.7, rounded up to 147 tiles. Boxes of 10 means 15 boxes. With 3 mm joints and 8 mm tiles the grout is about 3.1 kg.
For planks, the same 12 m² plus 10% is 13.2 m². Boxes of 2.2 m² make exactly 6 boxes.
FAQs
Should I round the tiles before adding waste? No. Waste is added to the exact count, then rounded once, so you are not rounding up twice.
Why buy extra? Tiles and planks change shade between batches. Keep spares from the same batch.
Does it work for walls? Yes. Use wall width times height, and take away windows.
Where the numbers come from
- Area, tile count and grout joint volume: fibub's own working. Waste allowances (10% straight, 15% diagonal or herringbone) and grout at 1.6 kg per litre of joint are rules of thumb; check the box and the bag.
Standard scientific values, such as constants, atomic weights and melting points, are facts found in every textbook; we name where ours were checked. If you are an author or publisher and want a value, a credit or a table changed or removed, tell us and we will act quickly.
Read more on the Blog
- How many tiles do I need? Tiles, grout and flooring boxes(the full guide)
Last updated 2026-11-10.