Tile and flooring calculator
Enter the room size and the size of one tile. You get the number of tiles to buy, with a waste allowance, the boxes and the cost.
Free · no signup Runs in your browser
How many tiles do I need for a floor?
Divide the floor area by the area of one tile, add an allowance for cuts and breakage, and round up. A 4 m × 3 m room is 12 m². A 30 cm × 30 cm tile covers 0.09 m², so the room needs 12 ÷ 0.09 = 133.3 tiles. With 10% waste that is 13.2 m² ÷ 0.09 = 146.7, so buy 147 tiles. If tiles come in boxes of 10, that is 15 boxes. The calculator also handles a second rectangle, such as a hallway.
Why we built this calculator
Tile and flooring jobs go wrong in two ways: you run short and the next batch is a slightly different shade, or you over-buy and pay for boxes you cannot return. Working out the right number is only a matter of area, but there are traps: the unit of the tile (centimetres or inches), the unit of the room, the allowance for waste and the fact that tiles are sold in boxes. This calculator handles all of them and shows the working.
Everything is worked out in your browser. Nothing you enter is sent anywhere.
How it works
The floor area is the length times the width; a second rectangle, such as an alcove or a hallway, can be added. The area of one tile is its length times its width, converted so both are in the same unit as the room: for metric, centimetres squared divided by 10,000 gives square metres; for imperial, inches squared divided by 144 gives square feet. The waste allowance multiplies the area by (1 + waste), covering cuts at the edges, breakage and mistakes. Dividing by the tile's area and rounding up gives the whole tiles needed. If tiles are sold by the box, dividing by the tiles per box and rounding up gives the boxes, and the spare tiles are shown. A price per tile gives the cost of the full boxes.
How to use it
- Choose metric or imperial, and enter the room's length and width. Add a second rectangle if the room is L-shaped.
- Enter the length and width of one tile, in centimetres or inches. Use the tile size without the grout line.
- Choose a waste allowance: 5 to 10% for straight layouts, more for diagonal, herringbone or patterned work.
- Enter tiles per box and a price per tile if you want the boxes and the cost.
- Round up to full boxes, and keep a few spare tiles for repairs.
Use cases
- Tiling a bathroom, kitchen, hallway or patio
- Laying laminate, vinyl plank or engineered flooring by the piece
- Comparing prices of tiles in different sizes
- Checking a quote from a contractor
- Working out spare tiles for future repairs
- Estimating wall tiles by using the wall's length and height
Problems you may run into
Most trouble is about waste and sizes.
| What you see | Likely cause | What to do |
|---|---|---|
| I ran short | The waste allowance was too small, or the layout needs many cuts | Use 10 to 15% for diagonal, large-format or patterned layouts |
| The tile size on the box does not match | Boxes may give the nominal size, or the size with grout | Measure one tile, and use its real size |
| The area is in the wrong unit | Room in feet and tile in centimetres | Choose one unit system for both; the tile fields follow it |
| Planks, not square tiles | A plank is also a rectangle | Enter its length and width |
| Cutouts and fixtures | Tubs and islands are not taken off | Subtract their area from the room size, or add less |
| Different batches | Colour can vary between production lots | Buy all boxes at once and mix tiles from different boxes as you lay them |
Planning the job
Measure the room twice, at the widest points, and sketch it. Dry-lay a few tiles to see how the edges fall, so that you do not end with a thin sliver along a wall. Check the floor is flat and clean, and that the tile and adhesive suit the room: bathrooms and entries need tiles rated for wet or heavy use. Keep a few spare tiles from the same batch in case of a later repair.
The formula
How the answer is worked out.
floor area = length × width (+ the second rectangle)tile area = tile length × tile width (cm² ÷ 10,000 = m²; in² ÷ 144 = sq ft)tiles = floor area × (1 + waste) ÷ tile area, rounded upboxes = tiles ÷ tiles per box, rounded up
Tiles are counted whole. Grout lines are not counted. Waste is a general guide; patterned layouts can need more. Cost uses the price per tile and, when you give a box size, the full boxes.
Example: 4 m × 3 m with 30 cm tiles
10% waste, boxes of 10.
- Floor4 × 3 = 12 m²
- One tile30 × 30 = 900 cm² = 0.09 m²
- With 10% waste13.2 ÷ 0.09 = 146.7, so 147 tiles
- Boxes147 ÷ 10 = 14.7, so 15 boxes (150 tiles, 3 spare)
147 tiles, 15 boxes
Without waste: 133.3, so 134 tiles.
Terms on this page
- Waste allowance
- Extra material bought to cover cuts, breakage and mistakes.
- Nominal size
- The size a tile is called, which can differ slightly from its real size.
Common questions
How do I calculate how many tiles I need?
Divide the floor area by the area of one tile, add waste and round up.
How much waste should I add?
About 5 to 10% for straight layouts, more for diagonal or patterned ones.
Does it work for laminate and vinyl planks?
Yes. Enter the plank's length and width.
Does it include grout?
No. Use the tile size without the grout line.
What about wall tiles?
Use the wall's length and height as the room's length and width.
Is anything I enter sent to a server?
No. The calculation happens in your browser and nothing you type leaves your device.
What to work out next
Where these numbers come from
- Wikipedia — Tile Common tile materials, uses and sizes.
- Wikipedia — Area How areas of rectangles are worked out.
Last verified 2026-10-25 The method on this page is checked against the sources above at least once a year. Spotted something out of date? Tell us and we will fix it.
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