Home Improvement
How Many Tiles Do I Need? Floor and Wall Tile Calculation
The tile formula, counts and boxes for a 12 × 10 ft room in five tile sizes, how much extra to buy, and tiling walls and bathrooms.
By Team Vind · Updated · 4 min read
Tiles are sold by the box, shades vary from batch to batch, and running short halfway through a floor is a real problem. So it pays to work out the number properly: the area, the tile size, and enough extra for cuts and breakage.
The formula
Tiles = area ÷ area of one tile, + 10% extra
A 12 × 10 ft room is 120 sq ft. A 600 × 600 mm (2 × 2 ft) tile covers 3.88 sq ft. So 120 ÷ 3.88 = 31 tiles allowing for a 2 mm grout gap, plus 10% = 34 tiles. At 4 tiles a box, that's 9 boxes.
Tiles for a 12 × 10 ft room by tile size
| Tile size | Sq ft per tile | Tiles (with 10%) | Typical box | Boxes |
|---|---|---|---|---|
| 300 × 300 mm (1 × 1 ft) | 0.97 | 135 | 10 tiles | 14 |
| 300 × 600 mm (1 × 2 ft) | 1.94 | 68 | 8 tiles | 9 |
| 600 × 600 mm (2 × 2 ft) | 3.88 | 34 | 4 tiles | 9 |
| 600 × 1200 mm (2 × 4 ft) | 7.75 | 17 | 2 tiles | 9 |
| 800 × 800 mm | 6.89 | 20 | 3 tiles | 7 |
Try it: Tile Calculator
Tiles Needed
How much extra to buy
- 5–10% for a straight layout in a simple rectangular room.
- 12–15% for diagonal or herringbone patterns, or rooms with many corners and pillars.
- More for large tiles (600 × 1200 mm and up), because every cut wastes a bigger piece.
Keep 4–6 spare tiles after the job. Replacing a cracked tile years later is easy if you have one from the same batch.
Walls and bathrooms
Work out each wall separately: width × height, minus doors and windows. A 7 × 5 ft bathroom tiled to 7 ft has walls of 2 × (7 + 5) × 7 = 168 sq ft, minus about 14 sq ft for the door, so 154 sq ft of wall tiles, plus 35 sq ft of floor. Use anti-skid tiles on bathroom floors.
Measuring an odd-shaped floor? The square feet calculator handles it. Painting the walls as well? See how much paint for a room.
Frequently asked questions
How many 2 × 2 tiles do I need for 100 sq ft?
About 29 tiles of 600 × 600 mm, including 10% extra.
How many sq ft is a 600 × 600 tile?
3.88 sq ft (0.36 m²).
How much extra tile should I buy?
About 10% for a straight layout, 15% for diagonal patterns or rooms with many cuts.
How do I calculate tiles for a wall?
Multiply each wall's width by the tiling height, subtract doors and windows, add the walls together, then divide by the tile's area and add 10%.
Sources
Last reviewed: 10 October 2026