Tile & Flooring Calculator
(Tiles, Planks and Boxes With Waste)
Enter your room and tile size to find how many tiles or planks you need, with a waste allowance for your layout and the number of boxes to buy.
Units
Feet or metres, depending on the unit above
Bathtub, kitchen island or built-ins, in square feet or square metres
Inches or centimetres
Layout (waste allowance)
Read it on the box to see how many boxes to buy
Result
💡 Formula Guide
How to Calculate How Many Tiles You Need
The number of tiles you need is the room area divided by the area of one tile, plus an allowance for cuts and breakage. Getting it right matters because running short can leave you waiting on a reorder that may not match, while ordering far too many wastes money. A tile calculator turns the room size and tile size into tiles and boxes in seconds, and lets you adjust the waste percentage to suit the layout you plan to use.
Example. A 12 × 10 ft room is 120 square feet. A 12 × 12 inch tile covers 1 square foot. With a straight lay and 10% waste you need 120 × 1.10 = 132 tiles. If tiles are sold 10 to a box, that is 13.2 boxes, so buy 14 boxes (140 tiles), leaving 8 spares. For a diagonal layout at 15% waste the total rises to 138 tiles, or 14 boxes. In metric, a 4 × 3 m room with 30 × 30 cm tiles (0.09 m² each) needs 12 ÷ 0.09 × 1.10 = about 147 tiles.
Choosing a Waste Allowance
| Layout | Common allowance | Why |
|---|---|---|
| Straight lay in a simple rectangular room | About 10% | Edge cuts and a few breakages |
| Diagonal, herringbone or offset pattern | About 15% | More angled cuts and unusable offcuts |
| Small or irregular rooms with many fixtures | 15% or more | Many cuts around toilets, vanities and corners |
| Large-format or patterned tile | Ask your supplier | Fewer, larger cuts and matching patterns raise waste |
Waste depends on the room as much as the pattern. A long straight hallway wastes less than a bathroom with a tub, toilet and vanity, because cuts around fixtures rarely reuse the offcut. If you are unsure, err on the higher side: an unused box can often be returned, but a short order rarely is.
💡 Tip: keep 1 or 2 spare tiles for future repairs. If the style is discontinued, you will not be able to match it later, and a cracked tile in a finished floor is much easier to fix with a spare from the same batch.
Measuring the Room and the Tile
Measure the room's length and width in feet or metres and multiply. For an L-shaped room, split it into rectangles or use the Room Area Calculator. Subtract areas that will not be tiled, such as a bathtub or built-in cabinets, using the optional field. Then measure the tile: width times length in inches or centimetres, converted to square feet (divide by 144) or square metres (divide by 10,000).
Do not forget the grout joints. The calculation uses the nominal tile size, and thin joints have a small effect, but wide joints with small tiles can change the count slightly. If the tile is sold by coverage per box, use the box's stated coverage to double-check the number of boxes from this calculator.
Ordering and Installation Tips
- Order everything at once and check that all boxes share the same batch or dye lot number, since colour varies between production runs.
- Do a dry layout before fixing anything, so you can plan cuts and avoid slivers at the walls.
- Ask about adhesive and grout quantities separately, since they depend on tile size and joint width.
- Prepare the substrate. A flat, clean, sound base matters more than any calculation for a lasting floor.
Once the floor is planned, you can price the rest of the room: use the Paint Coverage Calculator for the walls and the Wallpaper Coverage Calculator if you are papering a feature wall. This calculator gives an estimate for planning; your supplier can confirm final quantities and any minimum order sizes.
Frequently Asked Questions About How Many Tiles to Buy
How many tiles do I need for a room?
Divide the room area by the area of one tile, then add a waste allowance. A 12 × 10 ft room is 120 sq ft, and 12 × 12 inch tiles cover 1 sq ft each, so 120 tiles plus 10% waste comes to 132. If a box holds 10 tiles, buy 14 boxes.
How much extra tile should I buy?
Suppliers commonly recommend about 10% extra for a simple straight layout and about 15% for diagonal or herringbone patterns, or rooms with many cuts around fixtures. Large-format tile and intricate patterns can need more. The calculator lets you set any percentage.
Why do I need waste at all?
Tiles must be cut to fit the edges, corners and fixtures, and the offcuts often cannot be reused. Some tiles will also crack or be defective. The extra tile also gives you spares for future repairs, which matters if the design is later discontinued.
How do I calculate the area of one tile?
Multiply width by length. A 12 × 24 inch tile is 288 square inches, which is 2 square feet after dividing by 144. In metric, 30 × 30 cm is 900 square centimetres, or 0.09 square metres after dividing by 10,000.
How many boxes should I buy?
Divide the tiles needed, including waste, by the number of tiles per box and round up. Boxes are usually labelled with both the tile count and the coverage in square feet, so use whichever you prefer, and always round up to the next whole box.
Does the calculator include grout or adhesive?
No. It counts only tiles or planks. Grout and adhesive depend on tile size, joint width and thickness, and the manufacturer's coverage figures are the best guide, so ask your supplier for quantities based on the area in square feet.
Should all tiles come from the same batch?
Yes. Colour and size can vary slightly between production batches, sometimes called dye lots, and a mismatch is more visible on a large floor. Buy everything at once, check that the box numbers match and keep a few spare tiles from the same batch.
Can I use this for wood or vinyl planks?
Yes. Enter the plank width and length in place of tile dimensions, and choose a waste percentage suited to the layout. Plank floors often use around 10% waste, but staggered patterns and awkward rooms can need more.
Last Updated: September 2026 | Waste allowances (about 10% straight, 15% diagonal) are common supplier recommendations, not fixed rules. Confirm quantities with your tile supplier.