Tile Calculator
Free tile calculator for floors, walls and backsplashes. Enter area and tile size to get the number of tiles and boxes, pounds of grout and bags of thinset.
3/8 in = 0.375
10% straight, 15% diagonal or large-format
- Tiles
- 44
- incl. 10% extra
- Boxes
- 6
- Area
- 80 sq ft
- buy 88 sq ft
- Tile cost
- $288
Setting materials
| Grout1 × 25 lb bag, incl. 10% extra | 4.1 lb |
| Thinset mortar50 lb bags, 1/4 × 3/8 in square notch trowel | 2 bags |
Price
$288
Tile only (full boxes), before setting materials and tax
Default prices are typical U.S. retail figures, reviewed November 2026. Enter your supplier's prices for an exact total.
Tile is sold by the box or by the square foot, but you need to know the number of tiles to plan a layout, and grout and thinset are bought separately. Grout quantity depends on the tile size, the joint width and the tile thickness.
Enter the area and tile size. The calculator gives the number of tiles and boxes with a waste allowance, the pounds of grout and the bags of thinset mortar, with a suggested trowel size.
How to use the tile calculator
- Measure the floor or wall area in square feet.
- Divide by the area of one tile including the grout joint.
- Add 10% for cuts, or 15% for diagonal layouts and large-format tile.
- Work out grout from the joint width, tile thickness and tile size.
- Allow one 50 lb bag of thinset per 40 to 50 sq ft for most floor tile.
Tiles = area × (1 + waste) ÷ ((w + joint) × (l + joint) ÷ 144). Grout (in³ per sq ft) = (w + l) ÷ (w × l) × joint × thickness × 144.
Tiles per 100 sq ft by size
1/8 in grout joint, before waste.
| Tile size | Tiles per 100 sq ft |
|---|---|
| 3 × 6 in subway | 753 |
| 4 × 4 in | 847 |
| 6 × 24 in plank | 98 |
| 12 × 12 in | 98 |
| 12 × 24 in | 50 |
| 18 × 18 in | 44 |
| 24 × 24 in | 25 |
Tips before you buy
- Buy all tile from the same lot so color and size match, and keep a box for repairs.
- Large-format tile (any side 15 in or more) needs a flat substrate and large-and-heavy-tile mortar.
- Use unsanded grout for joints of 1/8 inch or less on polished stone, and sanded grout for wider joints.
- Dry-lay a row in each direction before you mix mortar so cut pieces at the walls aren't too thin.
Frequently asked questions
How many tiles do I need for 100 square feet?
With 12 × 12 inch tile and a 1/8 inch joint, about 98 tiles before waste, or 108 with 10% extra. With 12 × 24 inch tile, about 50, or 55 with waste.
How much grout do I need?
For 100 square feet of 12 × 12 inch tile 3/8 inch thick with a 1/8 inch joint, about 7 pounds. Small tiles need far more: 3 × 6 subway tile needs about 20 pounds for the same area.
How much thinset do I need?
A 50 lb bag covers about 40 to 50 square feet with a 1/4 × 3/8 inch notched trowel for floor tile, or about 90 square feet with a 1/4 × 1/4 inch trowel for small wall tile.
How much extra tile should I buy?
Buy 10% extra for straight layouts and 15% for diagonal, herringbone or large-format tile, plus a few spare tiles for future repairs.