Tile Calculator: How Many Tiles Do I Need?
Work out how many tiles you need for a floor or wall, how many boxes to buy, and how much tile adhesive, grout and spacers to get, with a shopping list you can copy.
No sign-up required. Free to use, with every formula shown on this page. Last reviewed October 2026.
Work out your tiles
Tile Calculator
Work out how many tiles a floor or wall needs, how many boxes to buy, and the adhesive, grout and spacers to go with them.
1 What you're tiling
Split an L-shaped room into two rectangles.
Areas to leave out2 The tiles
Tile size (mm)It's on the box or the shop's page, often as "1,08 m² per box".
3 Adhesive, grout and extras
Metres of tile edges that will show, such as outside corners or the top of a splashback.
4 Prices (optional)
Add the prices you've seen to get a total. Leave any box empty to skip it.
Tiles you need
0 tiles
Area to tile
0 m²
Extra tiles
0
Cost
–
What you'll need
Breakdown
| Area | Size | m² |
|---|
How it's worked out: tiles = area × (1 + extra %) ÷ the area of one tile, rounded up (joints are ignored, which errs on the safe side). Adhesive = area × the amount for your trowel notch (powder: 6 mm 1,8, 8 mm 2,3, 10 mm 2,8, 12 mm 3,5 kg per m²; ready-mixed 3,0 kg per m²), plus 10%. Grout = (tile length + width) ÷ (length × width) × joint × tile thickness × 1,6 kg per m², plus 10%: the formula grout makers publish. Spacers: about one per tile.
Estimates only. Adhesive and grout use varies with the floor or wall, the tile and how you spread it: check the bag. Buy all your tiles from the same batch and keep a few spare for repairs.
How it works
Tiles, boxes, adhesive and grout
The calculator works out the area to tile, adds extra for cuts, then turns it into tiles, boxes and a shopping list. The sources and assumptions behind it are on our How we calculate page.
Measure the area
Each floor or wall is width × length or height. Add more areas for an L-shaped room or each wall of a shower, and take away anything you won’t tile, such as a bath, a window or kitchen units.
Add extra for cuts
Tiles at the edges have to be cut, and some break. Straight and brick-bond layouts need about 10% extra, diagonal 15% and herringbone about 20%. The tiles are then divided into whole boxes, from the tiles or m² per box on the label.
Adhesive and grout
Adhesive depends on the notched trowel: bigger tiles need a bigger notch and more adhesive, from about 1.8 kg per m² with a 6 mm notch to 3.5 kg with 12 mm. Grout is worked out from the joint width, the tile thickness and the tile size, with the formula grout makers publish.
Examples
How many tiles for a bathroom, kitchen or shower?
The same calculator, a few common jobs. Small tiles add up quickly: a short metro-tile splashback takes nearly 180 tiles.
Illustrative only, from the calculator above. Tiles include 10% extra (20% for herringbone); adhesive and grout include 10%. Notched trowel suggested from the tile size: 6 mm for the metro tiles, 8 mm up to 400 mm, 10 mm up to 600 mm and 12 mm for the planks. Grout for 3 mm joints on floors and 2 mm on walls.
Tips
Before you start tiling
A good tiling job is mostly planning: measuring well, buying enough from one batch and preparing the surface.
Buy from one batch
Tiles vary slightly in shade between production batches. Check the batch (shade) number on every box matches, buy everything at once, and keep a few spare tiles for future repairs: the same batch can be impossible to find later.
Prepare the surface
Floors and walls need to be firm, flat, clean and dry. Prime dusty or very absorbent surfaces, such as plaster or a sand and cement screed. On wooden floors or over underfloor heating, use a flexible adhesive and, on timber, a tile backer board.
Plan the layout
Lay the tiles out dry first and start from the middle of the room or wall, so the cut tiles at each edge are the same size and not thin slivers. In showers and other wet areas, waterproof (tank) the walls and floor before tiling.
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Common questions
Frequently asked questions about how many tiles you need
Common questions about tiles, boxes, adhesive and grout.
How many tiles do I need for a bathroom?
Measure each floor or wall to be tiled, take away the bath, shower tray, door and window, and add 10% for cuts. A small bathroom floor of 2.0 × 1.7 m needs 42 tiles of 300 × 300 mm. Walls 2.4 m high in the same room need about 94 tiles of 300 × 600 mm. The calculator works it out for your own room.
How much extra tile should I buy?
About 10% extra for a straight or brick-bond layout, 15% for a diagonal layout and about 20% for herringbone, because those need more cuts at the edges. Buy a little more if the room has lots of corners, or if you’re new to tiling.
How much tile adhesive do I need per m²?
It depends on the notched trowel. Powder adhesive uses about 1.8 kg per m² with a 6 mm notch, 2.3 kg with 8 mm, 2.8 kg with 10 mm and about 3.5 kg with 12 mm, so a 20 kg bag covers roughly 6 to 11 m². Ready-mixed wall adhesive uses about 3 kg per m². Check the bag for your product.
How much grout do I need?
Grout in kg per m² = (tile length + tile width) ÷ (length × width) × joint width × tile thickness × 1.6, with all sizes in millimetres. For 300 × 600 mm tiles 10 mm thick with 3 mm joints, that’s about 0.24 kg per m², so a 2.5 kg bag grouts about 10 m². Small tiles have far more joints and take more grout.
What size trowel for 600 × 600 tiles?
A 10 mm notched trowel is usual for tiles up to about 600 mm. For larger tiles, use a 12 mm notch and spread adhesive on the back of each tile as well (back-buttering), so there are no hollow spots that could crack.
Can I use ready-mixed tile adhesive on a floor?
Usually not. Ready-mixed tub adhesives are made for wall tiles, and most are only for lighter tiles. For floors, showers and large or heavy tiles, use a powder (cement-based) adhesive. Always check the tub.
Are the results exact?
No. They are estimates: the real number of tiles depends on the layout and how many cuts you need, and adhesive and grout use varies with the surface and how you spread it. The calculator adds extra for each, but it’s worth keeping a few spare tiles from the same batch.