How many tiles do I need?
Enter the size of the floor or wall, the tile size, and the grout gap. The tiles to buy, with an extra share for waste, update as you type. Add the tiles per box to get the boxes.
- Tiles to buy
- 130
For 120 ft², buy 130 tiles (129.29 before rounding up).
- Tiles, not rounded
- 129.29
- Tiles with no extra
- 118
- Area, ft²
- 120
- Area, m²
- 11.15
Tiles to buy: 130. For 120 ft², buy 130 tiles (129.29 before rounding up).
How to calculate
Computes how many tiles cover a floor or wall from its size, the tile size, and the grout gap, with an extra share for cuts and breakage, and the boxes to buy.
Example with the default inputs (Area length 12 ft, Area width 10 ft, Tile length 12 in, Tile width 12 in, Grout gap 0.125 in, Extra for waste 10%): For 120 ft², buy 130 tiles (129.29 before rounding up).
Method: tiles = length × width × (1 + extra ÷ 100) ÷ ((tile length + gap) × (tile width + gap)), rounded up; boxes = tiles ÷ tiles per box, rounded up.
- The area is a rectangle. Split an L-shaped room into rectangles and add the tiles.
- Each tile covers its own size plus one grout gap in each direction.
- Extra for waste is 10% by default (Daltile: about 10% more); use about 15% for diagonal, herringbone, or large tiles (Arizona Tile: 10% to 15%).
- Tiles are counted by area; the count does not plan where cuts fall.
Worked examples
Each example is checked against the calculator on every build.
- Area length 12 ft, Area width 10 ft, Tile length 12 in, Tile width 12 in, Grout gap 0 in, Extra for waste 10% gives Area, ft² 120, Tiles, not rounded 132, Tiles to buy 132, Tiles with no extra 120.Source: Daltile, Tile & Stone FAQs: buy about 10% more tile than you need (https://www.daltile.com/how-to/faqs)
- Area length 12 ft, Area width 10 ft, Tile length 12 in, Tile width 12 in, Grout gap 0.125 in, Extra for waste 10%, Tiles per box 15 gives Tiles, not rounded 129.29238, Tiles to buy 130, Tiles with no extra 118, Boxes to buy 9.Source: Daltile, Tile & Stone FAQs: buy about 10% more tile (https://www.daltile.com/how-to/faqs)
- Area length 9.843 ft, Area width 7.874 ft, Tile length 11.81 in, Tile width 23.62 in, Grout gap 0.1181 in, Extra for waste 15% gives Area, m² 7.2, Tiles, not rounded 45.317965, Tiles to buy 46.Source: Arizona Tile, How Much Extra Tile To Buy: 10% to 15% extra (https://www.arizonatile.com/how-much-extra-tile-to-buy/)
How it works
- Area = length × width of the floor or wall.
- Area one tile covers = (tile length + grout gap) × (tile width + grout gap). Each tile takes its own size plus one grout joint on two sides.
- Tiles, not rounded = area × (1 + extra ÷ 100) ÷ area one tile covers.
- Tiles to buy = tiles, not rounded, rounded up to a whole tile.
- Boxes to buy = tiles to buy ÷ tiles per box, rounded up (only when you enter the tiles per box).
The result panel also shows the tiles with no extra (area ÷ area one tile covers, rounded up) and the area in square feet and square meters.
Assumptions
- The area is a rectangle. For an L-shaped or other room, split it into rectangles and add the counts.
- Extra for waste defaults to 10%, from Daltile’s advice to buy about 10% more tile. Arizona Tile gives 10% to 15%; use about 15% for diagonal or herringbone layouts and large tiles. You can type any extra from 0% to 100%.
- Tiles are counted by area. The count does not plan where cut pieces fall, so a layout with many small cuts may need the higher extra.
- The arithmetic is exact on the sizes you type (feet, inches, meters, centimeters, or millimeters, from the exact NIST definitions), so a floor that takes a whole number of tiles is never rounded up by a rounding error.
Rules
- Every size must be more than 0, except the grout gap, which may be 0. A tile must be at least 1 mm on each side.
- Extra for waste is from 0% to 100%.
- Tiles per box, if entered, is a whole number of 1 or more.
Worked examples by hand
12 × 10 ft floor, 12 × 12 in tiles, no gap, 10% extra. Area = 120 ft². Each tile covers 1 ft². Tiles = 120 × 1.1 ÷ 1 = 132 tiles, exactly; with no extra, 120.
12 × 10 ft floor, 12 × 12 in tiles, 1/8 in gap, 10% extra, 15 tiles per box. Area = 144 × 120 = 17,280 in². Each tile covers 12.125 × 12.125 = 147.015625 in². Tiles = 17,280 × 1.1 ÷ 147.015625 = 129.29, so 130 tiles. With no extra: 17,280 ÷ 147.015625 = 117.54, so 118. Boxes = 130 ÷ 15 = 8.67, so 9 boxes.
3 × 2.4 m floor, 30 × 60 cm tiles, 3 mm gap, 15% extra. Area = 7.2 m². Each tile covers 0.303 × 0.603 = 0.182709 m². Tiles = 7.2 × 1.15 ÷ 0.182709 = 45.32, so 46 tiles.
Other questions people ask
How do I calculate how many tiles I need?
Multiply the length by the width to get the area. Add the grout gap to each side of one tile and multiply those to get the area one tile covers. Divide, add about 10% for waste, and round up. A 12 × 10 ft floor of 12 in tiles with 1/8 in grout needs 130 tiles.
How much extra tile should I buy?
About 10% for a straight layout, which Daltile recommends. Tile sellers such as Arizona Tile suggest 10% to 15%; use the high end for diagonal or herringbone layouts, large tiles, and rooms with many corners, because those need more cuts.
Does the grout gap change the tile count?
Yes, a little. Each tile covers its own size plus one gap in each direction. With 12 in tiles and a 1/8 in gap, a tile covers 12.125 × 12.125 in, so a floor needs about 2% fewer tiles than with no gap.
How do I tile an L-shaped room?
Split it into rectangles, enter each one, and add the tile counts. Round each part up, or add the unrounded counts and round once to buy a little less.
How many square feet does a box of tile cover?
The box label gives it, usually as square feet per box. This calculator counts tiles, so enter the tiles per box from the label to get the boxes to buy.
Should I keep spare tiles?
Yes. A few spare tiles from the same batch let you replace a cracked tile later; a new batch can differ in color. The extra for waste usually leaves some.