Tile Calculator
Updated 2026-10-12
Enter the area you're tiling and the size of your tile. The calculator adds a waste allowance for cuts and breakages and tells you how many tiles and boxes to buy.
How the tile calculator works
First the calculator finds the area of the floor or wall. Then it works out how much area one tile covers and divides one by the other. Finally it adds a percentage for waste, because some tiles will be cut along the edges and a few will break or have defects.
The tile size is entered in inches (or centimeters) because that's how tiles are sold. Behind the scenes, a 12 × 12 inch tile becomes 1 sq ft, and a 30 × 30 cm tile becomes 0.09 m².
Worked example
A 10 × 8 ft bathroom floor is 80 sq ft. With 12 × 12 inch tiles, each tile covers 1 sq ft, so you need 80 tiles. Adding 10% for waste gives 88 tiles. If tiles come 10 to a box, you need 9 boxes.
How much waste should I allow?
| Layout | Suggested waste |
|---|---|
| Straight lay in a simple rectangular room | 5–10% |
| Straight lay with obstacles (toilet, cabinets, doorways) | 10% |
| Diagonal layout | 15% |
| Herringbone, chevron or other patterns | 15–20% |
| Large-format tiles (24 in / 60 cm and bigger) | Add an extra 5% |
Large tiles waste more because each offcut is bigger, and a single broken tile is a bigger share of the total.
Measuring awkward rooms
If your room is L-shaped, split it into two rectangles, run the calculator for each, and add the results. For a wall, measure only the part you're tiling, such as the backsplash height, and subtract windows or large openings. For a shower, measure each wall separately and add them up.
Tips before you buy
- Check the batch (lot) number. Tiles from different production runs can differ slightly in color. Buy everything from the same lot.
- Keep a few spares. Store a handful of leftover tiles. If one cracks years later, matching it may be impossible.
- Grout lines don't change much. The joints between tiles slightly reduce how many tiles you need. The calculator ignores this, which gives you a small extra margin.
- Dry-lay first. Laying out a row of tiles without adhesive helps you see where cuts will fall and avoid thin slivers at the walls.
Tiles per square foot by size
A handy way to check the calculator, or to compare tile sizes in the store. Figures are before waste.
| Tile size | Area of one tile | Tiles per sq ft | Tiles per 100 sq ft |
|---|---|---|---|
| 4 × 4 in | 0.111 sq ft | 9 | 900 |
| 6 × 6 in | 0.25 sq ft | 4 | 400 |
| 12 × 12 in | 1 sq ft | 1 | 100 |
| 12 × 24 in | 2 sq ft | 0.5 | 50 |
| 18 × 18 in | 2.25 sq ft | 0.44 | 45 (44.4 rounded up) |
| 24 × 24 in | 4 sq ft | 0.25 | 25 |
Small mosaic tiles are usually sold on mesh sheets, often about 12 × 12 in. For those, enter the sheet size instead of the size of each little tile.
Frequently asked questions
- How many 12 × 24 tiles do I need for 100 sq ft?
- Each 12 × 24 inch tile covers 2 sq ft, so 100 sq ft needs 50 tiles. With 10% waste, buy 55 tiles.
- How many tiles are in a square meter?
- It depends on the size. About 11 tiles of 30 × 30 cm, about 6 tiles of 30 × 60 cm, and about 3 tiles of 60 × 60 cm make up one square meter, before waste.
- Can I return extra tiles?
- Many stores accept unopened boxes, but policies vary. Ask before you buy, especially for special-order tiles.