Tile formulas
| What | Formula | Example (10×12 room, 12×12 tiles) |
|---|---|---|
| One tile | length × width (mm) ÷ 304.8² | 300 × 300 ÷ 92,903 = 0.969 sq ft |
| Count | floor ÷ one tile | 120 ÷ 0.969 = 123.87 |
| To buy | count × (1 + wastage), rounded up | 123.87 × 1.07 = 132.54 → 133 |
| Boxes | to buy ÷ tiles per box, rounded up | — |
Examples
Bedroom: 10×12 ft, 12×12 tiles, 7% — 133 tiles.
Living room: 15×12 ft, 24×24 tiles, 7% — 180 ÷ 3.875 = 46.45, × 1.07 = 49.7 → 50 tiles. At 4 per box that’s 13 boxes (52 tiles = 201.5 sq ft); at Tk 90 a sq ft the cost is ≈ Tk 18,135 (example price).
Bathroom walls: 30 ft of wall, 7 ft high = 210 sq ft, 10×16 (250×400 mm) tiles, 10% — 210 ÷ 1.076 = 195.1, × 1.1 → 215 tiles.
Tiles per 100 sq ft (no wastage)
| Name | Real size | One tile | Per 100 sq ft |
|---|---|---|---|
| 12×12 | 300×300 mm | 0.969 sq ft | 103.2 |
| 16×16 | 400×400 mm | 1.722 sq ft | 58.1 |
| 24×24 | 600×600 mm | 3.875 sq ft | 25.8 |
| 12×24 | 300×600 mm | 1.938 sq ft | 51.6 |
| 10×16 (wall) | 250×400 mm | 1.076 sq ft | 92.9 |
| 32×32 | 800×800 mm | 6.889 sq ft | 14.5 |
What to know in Bangladesh
- Named in inches, made in millimetres: local factory tiles come in 300, 400, 600 and 800 mm sizes. The box shows the real size; check it before buying.
- Usually priced per sq ft: shops and showrooms quote tiles per square foot and sell whole boxes. Check both the box count and the total square feet.
- Same batch: even one design varies slightly in shade between batches. Buy everything at once, from one batch number.
- Keep spares: keep 2–4 extra tiles for later breakages; the same design may be gone later.
- Labour is separate: the mason is usually paid per sq ft, and the cement-sand or tile adhesive is extra.
More: how the math works
First the floor or wall area in sq ft: length × width. Then one tile’s area. Tile sizes are in millimetres and 1 ft = 304.8 mm, so 1 sq ft = 92,903 sq mm. A 600×600 mm tile = 360,000 ÷ 92,903 = 3.875 sq ft.
Area divided by one tile gives the count before wastage. Tiles at the edges and corners must be cut, many offcuts are useless, and some break. So wastage is added and the count is rounded up to whole tiles.
With tiles per box, the calculator rounds up to whole boxes, since shops rarely sell opened boxes. A per-sq-ft price is multiplied by the total area of the tiles bought; a per-tile price by the piece count.
Grout joints (2–3 mm) aren’t counted; this makes the count slightly high, which works as a small spare.