Tile Calculator: How Many Tiles & Boxes?
Calculate the number of tiles, boxes, grout and thinset mortar you need for a floor, wall, shower or backsplash.
A 10 × 10 ft floor tiled with 12×12 in tiles needs about 108 tiles: 100 sq ft ÷ 1.02 sq ft per tile (with a 1/8 in grout joint) plus 10% waste. Formula: area × 144 ÷ ((tile width + joint) × (tile length + joint)) × 1.10.
Your numbers
Result
How to calculate how many tiles you need
Divide the area to be tiled by the area one tile occupies (including its grout joint), then add a waste allowance for cuts and breakage.
tiles = area × tiles per sq ft × (1 + waste %)
Tiles per square foot by tile size
| Tile size | Tiles per sq ft (1/8 in joint) | Tiles for 100 sq ft (+10%) |
|---|---|---|
| 4 × 4 in | 8.46 | 931 |
| 6 × 6 in | 3.84 | 423 |
| 3 × 6 in | 7.52 | 828 |
| 12 × 12 in | 0.98 | 108 |
| 12 × 24 in | 0.49 | 55 |
| 16 × 16 in | 0.55 | 61 |
| 18 × 18 in | 0.44 | 49 |
| 24 × 24 in | 0.25 | 28 |
Waste by layout
| Layout | Suggested waste |
|---|---|
| Straight lay, rectangular room | 7–10% |
| Diagonal | 15% |
| Herringbone or complex patterns | 20% |
| Large-format tile (24 in+) | 15% |
| Small mosaic sheets | 5–10% |
Estimating grout
Grout depends on the joint width, tile size and tile thickness. The calculator uses: area × (L + W) ÷ (L × W) × joint width × tile thickness × 10.5, where 10.5 combines the 144 square inches in a square foot, a grout density near 110 lb/ft³ and roughly 15% waste. Buy a little extra — color can vary between batches.
Don't forget the rest of the job
Thinset mortar, backer board or uncoupling membrane, spacers, sealer and trim pieces all add to the list. For the other floor coverings, see the flooring calculator and carpet calculator; for the measurements themselves, try the square footage calculator.
Frequently asked questions
How many 12×12 tiles do I need per square foot?
A 12 × 12 tile covers one square foot, but with a 1/8 in grout joint each tile occupies slightly more, so you need about 0.98 tiles per square foot before waste.
How much extra tile should I buy?
Ten percent for simple layouts, 15–20% for diagonal, herringbone or large-format tile. Keep a few spares for repairs.
How many tiles do I need for a 10×10 room?
A 10×10 room is 100 square feet — about 108 12×12 tiles at 10% waste, or 9–10 boxes of 11.
How much grout do I need?
For 12×12 tile with a 1/8 in joint and 3/8 in tile it is roughly 0.08 lb per square foot; smaller tile, wider joints and thicker tile need more.
How do I calculate tile for a backsplash?
Multiply the backsplash length by its height (usually 18 inches = 1.5 ft), subtract outlets and windows, and add 10% waste.
How do I calculate tile for a shower?
Add the area of each wall (width × height), subtract the door or niche openings, then add 10–15% waste.
Do I include the grout joint in tile size?
Yes — the formula adds the joint to both tile dimensions, because grout takes up space between tiles.
How many boxes of tile do I need?
Divide the tiles needed by tiles per box and round up. Check the box label — many boxes list coverage in square feet rather than tile count.
Sources and further reading
- Tile Council of North America — TCNA: tile installation standards
These references support the general guidance on this page. The calculator applies the standard formulas shown above to the numbers you enter.
Related calculators
. Estimates only. Always confirm quantities with your supplier or a qualified contractor before ordering, and add extra for waste and site conditions.