Tile Calculator
- Updated
- Imperial and metric
- Free, no sign-up
Results
130 tiles for 120 ft²
Grout and thinset are typical estimates (grout at 100 lb/ft³ of joint plus 10%). The coverage chart on each bag is the final word. For other grout types, use the grout calculator.
How to use the tile calculator
- Measure each surface you will tile. For a floor, use the room's length and width and split L-shaped rooms into rectangles. For walls and showers, enter the width and tiled height of each wall as its own area with + Add area. If a bathtub or vanity covers part of the floor, enter only the open floor.
- Enter the actual tile size from the box and the grout joint width. In inches, type fractions as decimals: 1/8 = 0.125.
- Choose the layout pattern. The waste figure changes to a typical value for that pattern, and you can type your own.
- Optionally add the tiles per box and the price per box to get whole boxes and a cost.
- For grout and thinset, enter the tile thickness, a grout bag size and the trowel notch you plan to use.
Tile calculation formula
Tiles = Area (ft²) ÷ Tile footprint × (1 + waste %), rounded up
Boxes = Tiles ÷ Tiles per box, rounded up
L and W are the tile length and width and J is the joint width, all in inches. Each tile takes up its own size plus one joint in each direction. In metric, use centimeters and divide by 10,000 instead of 144 to get m².
Leaving the joints out makes the count a little high: by about 2% for 12-inch tiles with 1/8-inch joints, and about 6% for 4-inch tiles. The waste allowance is added after that.
Thinset bags = Area ÷ Coverage per bag, rounded up
T is the tile thickness in inches. The grout figure is an estimate for cement grout; the grout calculator explains it and lets you change the density and waste.
Worked example: a 10 × 12 ft bathroom floor
The floor is 120 ft². With 12 × 24 inch tiles and 1/8-inch joints, each tile takes up 12.125 × 24.125 inches, or 2.031 ft², so it takes 59.1 tiles to cover the floor. An offset layout with 10% waste gives 65 tiles. If the box label says 8 tiles per box, that is 9 boxes, with 7 tiles to spare.
With 3/8-inch-thick tiles, grout comes to about 6.4 lb including 10% extra, so one 10 lb bag. A 1/2 × 1/2 inch square-notch trowel is a common choice for tiles this large. At a typical 45 ft² per 50 lb bag, that is 3 bags of thinset.
How much extra tile to buy for each pattern
Every cut at an edge leaves an offcut you may not be able to use, and patterns with angled cuts along every wall leave more. These are rules of thumb: small rooms with many corners and pipes waste more.
| Pattern | Typical waste | Tiles for the 120 ft² example | Why |
|---|---|---|---|
| Straight (grid) | 10% | 65 | Tiles in rows and columns. Cuts only at the edges. |
| Offset / brick | 10% | 65 | Each row shifted by part of a tile. Cut pieces at row ends can often be reused. |
| Diagonal (45°) | 15% | 68 | Every edge tile is cut at an angle. |
| Herringbone | 20% | 71 | Usually laid with rectangular tiles. Angled cuts along every edge. |
Tiles per 100 square feet
With 1/8-inch joints. Whole tiles, rounded up.
| Tile size | Tiles to cover 100 ft² | Buy with 10% waste | Buy with 15% waste |
|---|---|---|---|
| 3 × 6 in | 752.3 | 828 | 866 |
| 4 × 4 in | 846.3 | 931 | 974 |
| 6 × 6 in | 383.8 | 423 | 442 |
| 6 × 24 in | 97.5 | 108 | 113 |
| 12 × 12 in | 97.9 | 108 | 113 |
| 12 × 24 in | 49.2 | 55 | 57 |
| 18 × 18 in | 43.8 | 49 | 51 |
| 24 × 24 in | 24.7 | 28 | 29 |
In metric, with 3 mm joints:
| Tile size | Tiles per m² | Buy for 10 m² with 10% waste |
|---|---|---|
| 20 × 20 cm | 24.27 | 267 |
| 30 × 30 cm | 10.89 | 120 |
| 30 × 60 cm | 5.47 | 61 |
| 60 × 60 cm | 2.75 | 31 |
| 60 × 120 cm | 1.38 | 16 |
Choosing a trowel for thinset
The trowel notch sets how much thinset ends up under each tile, and bigger tiles need deeper notches to bed fully. Tile industry standards call for at least 80% mortar contact in dry indoor areas and 95% in showers, other wet areas and outdoors. Lift a freshly set tile now and then to check.
| Square notch | Typical coverage per 50 lb bag | Per 20 kg bag | Often used for (rule of thumb) |
|---|---|---|---|
| 1/4 × 1/4 in | 95 ft² | 7.8 m² | Tiles up to about 8 in (20 cm) |
| 1/4 × 3/8 in | 65 ft² | 5.3 m² | About 8 to 16 in (20–40 cm) |
| 1/2 × 1/2 in | 45 ft² | 3.7 m² | About 16 in (40 cm) and larger |
Real coverage depends on the product, the flatness of the surface and whether you back-butter the tiles, which large tiles often need. Check the bag and type its figure into the calculator.
Tips for buying tile
- Buy from one lot. Boxes carry a shade or lot number, and color can vary between production runs. Buy everything at once and check the numbers match.
- Keep spares. A few leftover tiles make future repairs easy, because the same tile can be hard to find later.
- Check the real size. Some tiles sold as 12 × 24 inches are made to metric sizes such as 300 × 600 mm (about 11.8 × 23.6 inches). Use the size printed on the box.
- Limit the offset on long tiles. For tiles with a side longer than 18 inches, industry guidance limits a brick offset to about one third of the tile length unless the manufacturer says otherwise. Large tiles are rarely perfectly flat, and a half offset puts high and low points side by side.
- Plan the layout. Dry-lay a row or snap center lines first so the cut tiles at the walls are not thin slivers.
- Other floors. For laminate, vinyl plank or wood, use the flooring calculator. For outdoor pavers, use the paver calculator.
Frequently asked questions
How many tiles do I need for 100 square feet?
With 12 × 12 inch tiles and 1/8-inch grout joints, 100 sq ft takes about 98 tiles before waste. With 10% extra for cuts and breakage, buy 108 tiles. With 12 × 24 inch tiles, the same area takes about 49 tiles, or 55 with 10% extra.
How much extra tile should I buy?
A common rule of thumb is 10% extra for straight and offset layouts, about 15% for diagonal layouts and about 20% for herringbone, because angled cuts along the walls leave more offcuts. Small rooms with many corners need more. It is also worth keeping a few spare tiles for future repairs.
How many tiles are in a box?
It depends on the tile size and the manufacturer, so check the box label, which usually gives the number of tiles and the area one box covers. Enter the tiles per box and the calculator rounds up to whole boxes and shows how many tiles will be left over.
How much grout and thinset do I need for 100 square feet of tile?
For 12 × 12 inch tiles 3/8 inch thick with 1/8-inch joints, the calculator estimates about 7.2 lb of grout including 10% extra, so one 10 lb bag. With a 1/4 × 3/8 inch square-notch trowel at a typical 65 sq ft per 50 lb bag, you need two bags of thinset. Coverage varies by product, so check both bags.
Should I include the grout joints when counting tiles?
Yes, for an accurate count. Each tile takes up its own size plus one joint in each direction, so a 12-inch tile with 1/8-inch joints occupies 12.125 × 12.125 inches. That lowers the count by about 2% for 12-inch tiles and about 6% for 4-inch tiles. Add the waste allowance after that.