Tile & Flooring Calculator
Find how many tiles or flooring planks to buy for a floor or wall. Advanced adds several rooms, grout gap, laying pattern, boxes, cost, grout, adhesive, underlay and skirting.
Tiling a wall? Use the wall's width and height. For an L-shaped room, add it as two rectangles. Take away things you won't cover, like a kitchen island, a bath or a window.
Fractions work: type 1/8 for an eighth of an inch.
Typical: 5–10% straight, about 15% diagonal, 15–20% herringbone. Add more for small rooms with many cuts.
Worked out round the edge of each room you add. Take off doorways, and the shared edge where two areas join.
How your tiles are worked out
Floor area ÷ the area one tile covers, rounded up, plus extra for cuts.
- 1
Floor area
12 ft × 10 ft= 120 sq ft
- 2
One tile covers
12 × 12 in= 1 sq ft
- 3
Count the tiles
120 ÷ 1= 120 tiles
- 4
Add the waste
132 ÷ 1(10% extra)= 132 tiles
Read more: the formula, worked examples, waste by pattern, grout and adhesive
To find how many tiles you need, work out the area you're covering, then the area one tile covers (including its share of the grout joint), and divide. Round up to a whole tile, then add extra for cuts, breakages and spares. Flooring planks work the same way, without the grout joint, and are usually sold by the box.
The formula
floor area = length × width (add each room, take away cut-outs)
one tile covers = (tile length + gap) × (tile width + gap)
tiles with no waste = floor area ÷ one tile covers, rounded up
area to buy = floor area × (1 + waste % ÷ 100)
tiles to buy = area to buy ÷ one tile covers, rounded up
boxes = tiles to buy ÷ tiles per box, rounded up (or area to buy ÷ box coverage)
grout kg = floor area × (tile length + tile width) ÷ (tile length × tile width) × tile thickness × gap × 1.6 (sizes in mm, area in m²)
adhesive kg = floor area in m² × kg per m² for your trowel
skirting = 2 × (length + width) for each room − doorways
Worked example
A room 12 ft long and 10 ft wide is 12 × 10 = 120 sq ft. A 12 × 12 in tile is 1 ft × 1 ft = 1 sq ft, so with tiles butted together you need 120 ÷ 1 = 120 tiles. For a straight lay add 10%: 120 × 1.10 = 132 sq ft, so buy 132 tiles.
Now leave a 1/8 in grout gap. Each tile then covers 12.125 × 12.125 = 147.015625 sq in. The room is 120 × 144 = 17,280 sq in, so you need 17,280 ÷ 147.015625 = 117.54, rounded up to 118 tiles, or 117.54 × 1.10 = 129.29, so 130 tiles with 10% extra. If a box holds 10 tiles, buy 130 ÷ 10 = 13 boxes. At $2.50 a tile that is 130 × 2.50 = $325.
In metric: a 4 m × 3 m floor is 12 m². With 60 × 60 cm tiles and a 3 mm gap, each tile covers 0.603 × 0.603 = 0.363609 m². That is 12 ÷ 0.363609 = 33.0, so 34 tiles with no waste; laid on the diagonal with 15% extra, 13.8 ÷ 0.363609 = 37.95, so 38 tiles. Grout for 9 mm thick tiles: (600 + 600) ÷ (600 × 600) × 9 × 3 × 1.6 = 0.144 kg per m², × 12 m² = 1.73 kg.
Waste by laying pattern
| Pattern | Typical extra | Why |
|---|---|---|
| Straight (grid) | 5–10% | Cuts only at the edges |
| Brick / offset | 10% | Ends of each row are cut |
| Diagonal (45°) | 15% | Every edge tile is cut at an angle |
| Herringbone / chevron | 15–20% | Many angled cuts round the edge |
Add a few percent more for small rooms, rooms with many corners, large tiles, natural stone (colour varies) and if you're new to tiling. Keep a few spare tiles from the same batch for later repairs.
Common tile sizes
| Tile | Tiles per sq ft | Tiles per m² |
|---|---|---|
| 4 × 4 in | 9 | 96.9 |
| 12 × 12 in | 1 | 10.76 |
| 12 × 24 in | 0.5 | 5.38 |
| 30 × 30 cm | 1.03 | 11.11 |
| 60 × 60 cm | 0.26 | 2.78 |
| 60 × 120 cm | 0.13 | 1.39 |
These are with no grout gap. A gap makes each tile cover a little more, so you need slightly fewer.
Grout and adhesive
The grout formula is the one tile-grout makers print on their bags: the joint length per square metre times the joint size, times a typical 1.6 kg per litre. Epoxy and some other grouts are lighter or heavier, so check the bag. Adhesive (thinset) use depends mostly on the trowel notch: typically about 2.5 kg per m² for a 6 mm (1/4 in) notch, 3.5 kg for 10 mm (3/8 in) and 4.5 kg for 12 mm (1/2 in). Large tiles and uneven floors need a bigger notch and more adhesive.
Flooring planks
- Laminate, vinyl and wood are sold by the box. Use the area per box printed on the box for the most accurate count.
- Leave the expansion gap round the walls the maker asks for; it is hidden by the skirting and doesn't change how much you buy.
- Underlay covers the floor area edge to edge, so you need the floor area, rounded up to whole rolls.
- Let the planks settle in the room for the time the maker says before you lay them.
The waste, grout and adhesive figures are typical rules of thumb, not fixed rules; follow the maker's advice for your product. Tile sizes in shops are often nominal (a "60 × 60" tile can be 59.7 cm), so for big jobs use the real size printed on the box. Checked on 10 October 2026.
Common questions
How do I calculate how many tiles I need?
Divide the floor area by the area one tile covers, including the grout gap, then add extra for waste and round up. A 12 × 10 ft room with 12 × 12 in tiles butted together needs 120 tiles, or 132 with 10% extra.
How much extra tile should I buy for waste?
Typically 5–10% for a straight grid, 10% for brick or offset, 15% for diagonal and 15–20% for herringbone or chevron. Add a few percent more for small rooms, large tiles or natural stone, and keep a few spares from the same batch for repairs.
How many 60 × 60 cm tiles are in a square metre?
About 2.78 with no grout gap. A 12 m² floor with 3 mm gaps needs 34 tiles, or 38 laid on the diagonal with 15% extra. A gap makes each tile cover a little more, so you need slightly fewer.
How much grout do I need?
It depends on the tile size, thickness and gap. For 60 × 60 cm tiles 9 mm thick with a 3 mm gap, it's about 0.144 kg per m², so 1.73 kg for 12 m². Epoxy and some other grouts are lighter or heavier, so check the bag.
How much tile adhesive do I need?
It depends mostly on the trowel notch: typically about 2.5 kg per m² for a 6 mm notch, 3.5 kg for 10 mm and 4.5 kg for 12 mm. Large tiles and uneven floors need a bigger notch and more adhesive.
How many boxes of tiles or flooring do I need?
Divide the area to buy, including waste, by the area per box printed on the box, and round up. For tiles you can divide the number of tiles by tiles per box instead: 130 tiles at 10 a box is 13 boxes.
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