Tile Calculator
How many tiles and boxes to buy for a floor, wall or backsplash, with the right waste for your pattern, plus grout pounds and bags of thinset by trowel size.
Tiles = area (sq ft) × 144 ÷ ((tile length + joint) × (tile width + joint)), plus 10% (15% for diagonal or herringbone). With ⅛ in joints, 12 × 24 in tiles need 0.49 per sq ft and 12 × 12 in need 0.98. A 10 × 12 ft floor in 12 × 24 in tile takes about 65 tiles.
Tiles per square foot by size (⅛ in joints)
| Tile | Per sq ft | Per 100 sq ft (+10%) | Trowel |
|---|---|---|---|
| 12 × 12 in | 0.98 | 108 | ¼ × ⅜ in square |
| 12 × 24 in | 0.49 | 55 | ½ × ½ in square |
| 6 × 24 in plank | 0.97 | 108 | ½ × ½ in square |
| 3 × 6 in subway | 7.52 | 828 | ¼ × ¼ in square |
| 4 × 4 in | 8.46 | 931 | ¼ × ¼ in square |
| 18 × 18 in | 0.44 | 49 | ½ × ½ in square |
| 24 × 24 in | 0.25 | 28 | ½ × ½ in square |
| 2 × 2 in mosaic | 31.89 | 3,508 | ¼ × ¼ in square |
Waste by pattern
| Pattern | Extra to order |
|---|---|
| Straight or stacked | 10% |
| Brick offset | 10% |
| Diagonal | 15% |
| Herringbone | 15% |
Buy all boxes from the same lot (shade) number and keep a few spare tiles for repairs.
Frequently asked questions
How do I calculate how many tiles I need?
Find the area in square feet (length × width), divide by the area of one tile including its grout joint, and add 10% for cuts, or 15% for diagonal and herringbone layouts. Then divide by the square feet per box.
How many 12 × 24 tiles do I need for 100 sq ft?
About 50 tiles before waste, or 55 with 10% extra. Each 12 × 24 tile covers 2 sq ft.
How much grout do I need?
It depends on tile size, joint width and tile thickness: small tiles and wide joints use far more. 100 sq ft of 12 × 12 tile with ⅛ in joints takes about 8–10 lb; the same area of 2 × 2 mosaic takes several times that.
How much thinset do I need?
A 50 lb bag covers about 90–100 sq ft with a ¼ × ¼ in trowel, 60–65 sq ft with ¼ × ⅜ in, and 40–45 sq ft with ½ × ½ in. Larger tiles need the bigger notch.
Should I use sanded or unsanded grout?
Unsanded for joints narrower than ⅛ in and for polished stone or glass that sand could scratch; sanded for joints ⅛ in and wider.
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Tile counts include the grout joint in each tile's footprint. Grout volume = (tile length + width) × joint × depth ÷ (length × width) per unit area, at about 0.07 lb per cubic inch plus 15%. Thinset coverage per 50 lb bag reflects typical manufacturer data for each trowel notch; check your bag. Prices are placeholders to edit.