Boxes
9
Tile Calculator
How many tiles, and how many boxes — for a floor, a wall or a shower, with the right waste for your layout.
For a wall, this is the height.
Inches.
Inches.
More cuts means more waste.
Per cent. Override it if you know better.
Printed on the box. Leave 0 if buying loose tiles.
66 tiles
9 boxes, covering 120 ft² plus 10% waste.
Area
120 ft²
Estimated cost
—
With waste
132 ft²
Buy it all at once, from the same batch. Tile is made in production
runs and the shade shifts between them. The batch number is printed on the box. If
you run out halfway through and go back a fortnight later, the new tiles may not
match — and on a floor you will see it.
How this is worked out
length × width = area in square feet(tile width × tile length) ÷ 144 = area of one tile, because there are 144 square inches in a square footarea × (1 + waste) ÷ tile area = tiles, rounded uparea × (1 + waste) ÷ square feet per box = boxes, rounded up
Worked example — a 12 × 10 ft floor in 12 × 24 in tile
- Area:
12 × 10 = 120 sq ft - One tile:
12 × 24 ÷ 144 = 2 sq ft - With 10% waste:
120 × 1.10 = 132 sq ft - Tiles:
132 ÷ 2 = 66 - At 15.6 sq ft a box:
132 ÷ 15.6 = 8.46, so 9 boxes
How much waste to allow
| Layout | Waste | Why |
|---|---|---|
| Straight / stacked | 10% | Cuts only at the edges |
| Brick or offset | 15% | Every other row starts with a cut tile |
| Diagonal, herringbone | 20% | Every edge tile is an angled cut |
| Complex room | 25% | Alcoves, thresholds, pipework |
Large-format tile pushes all of these up. A 24 in tile cut badly wastes four times as much as a 6 in one, and you cannot use the offcut anywhere.
Questions people ask
Do I subtract the area the grout takes up?
No. Count the full tile size and ignore the grout lines. The joints are small enough that they fall inside the waste allowance, and working in nominal tile sizes is how boxes are sold anyway.
How do I do a shower with several walls?
Work out each wall separately and add them up, then apply the waste once at the end. Don't deduct the niche — you will use those tiles cutting the surround, and a niche usually needs more cuts than the area it saves.
What if my tiles are sold by the piece?
Set the square feet per box to 0 and use the tile count. Mosaic and some handmade tile is sold by the sheet or the piece rather than by area, in which case the tile count is the number that matters.
Should I keep the leftovers?
Yes, a box if you can. Tiles crack, and having matching replacements from the same batch years later is worth the shelf space. That is a real argument for rounding the box count up rather than shaving it.
How much thinset and grout?
That depends on the tile size and the trowel notch, and the bag tells you. As a rough guide, a 50 lb bag of thinset covers 80 to 100 sq ft with a 1/4 in square-notch trowel. Large-format tile needs a bigger notch and gets through noticeably more.