How Many 12x24 Tiles for 100 Square Feet?
Tiles needed
55 tiles
100 square feet, 12 by 24 tile, an eighth inch joint, 8 tiles a box, 10 percent waste.
Anything 15 inches or longer counts as large format. The substrate has to be flat inside an eighth of an inch over ten feet, the notch goes up to half by half, and every tile gets back buttered for coverage. Offset the joints by a third at most, because a running bond half offset on a long plank telegraphs every bit of tile warp as lippage.
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How that number is worked out
These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.
- Area to tile100 sq ft
- Tile width12 in
- Tile length24 in
- Tile thickness0.375 in
- Grout joint0.125 in
- Tiles per box8 each
- Waste allowance10 %
Tiles needed55 tiles
Anything 15 inches or longer counts as large format. The substrate has to be flat inside an eighth of an inch over ten feet, the notch goes up to half by half, and every tile gets back buttered for coverage. Offset the joints by a third at most, because a running bond half offset on a long plank telegraphs every bit of tile warp as lippage.
| Area with 10% waste | 110 sq ft |
|---|---|
| Coverage of one tile | 2.031 sq fttile plus one joint |
| Tiles per square foot | 0.49 |
| Boxes at 8 per box | 7 |
| Thinset, 50 lb bags | 3about 40 sq ft per bag at this tile size |
| Grout | 5.1 lbsold in 10 and 25 lb boxes |
| Backer board, 3 by 5 sheets | 7 |
The material list this produces
| Tile, boxes | 7 |
|---|---|
| Thinset mortar, 50 lb bags | 3 |
| Grout, lb | 6 |
| Tile spacers, each | 110 |
| Cement backer board, 3 x 5 sheets | 7 |
| Backer board screws, each | 280 |
Waste allowance compared
Waste is the only input here you choose rather than measure, and it is the one that decides whether the job finishes on a Saturday or on the following Saturday.
| Waste allowance | Tiles needed | Boxes at 8 per box |
|---|---|---|
| 5% | 52 tiles | 7 |
| 10% | 55 tiles | 7 |
| 15% | 57 tiles | 8 |
| 20% | 60 tiles | 8 |
What else matters here
One 12 by 24 with an eighth inch joint covers 2.031 square feet, not 2. Over 110 square feet of ordered area that difference is most of a tile, which does not sound like much until it is the tile that finishes the row at the doorway.
Fifty five tiles is 7 boxes at 8 a box, and a 12 by 24 box is heavy, around 60 pounds. Work out how you are getting them into the house before you get them into the truck.
Twelve by twenty four counts as large format under the flatness rule that starts at 15 inches, so the substrate needs to be within an eighth of an inch over ten feet and every tile wants back buttering. Keep the offset to a third rather than a half, because a running bond at a half on a plank tile puts the high point of one tile against the low point of its neighbor and gives you lippage down the whole row.
What this calculator assumes
- The tile count is worked out from the space one tile actually occupies, which is the tile plus one grout joint on two sides, not the tile on its own. On a 12 by 24 with an eighth inch joint that difference is about one percent, and on a mosaic it is far more.
- 10 percent waste suits a straight lay in a square room. A diagonal or herringbone lay wastes 15, and a room full of jogs, niches and closets can reach 20.
- Grout is figured geometrically: the joint volume is the space around each tile times the tile thickness, converted at 105 pounds per cubic foot, which is where sanded grout lands once mixed. Manufacturer coverage charts vary, so treat this as the order quantity and not the gospel.
- Thinset coverage follows the trowel, and the trowel follows the tile: about 85 sq ft from a 50 lb bag with a quarter inch notch under small tile, 60 under 12 inch, and 40 under large format where the notch grows and the tile gets back buttered.
Questions people ask
How many 12x24 tiles in 100 square feet?
50 to cover the bare floor at an eighth inch joint, 55 with 10 percent waste. That is 7 boxes at 8 tiles a box.
Is 12x24 tile considered large format?
Yes. Anything with a side of 15 inches or more is large format for flatness purposes, and 12 by 24 is treated as large format by every thinset maker. It needs a flat substrate, a large notch trowel, back buttering and a one third offset.
How much thinset does a bag cover?
It depends on the notch, and the notch follows the tile. A quarter by quarter square notch under small tile stretches a 50 pound bag across most of 85 square feet, a quarter by three eighths under a 12 inch tile gets about 60, and half by half under large format with back buttering is nearer 40. The bag states its own figure and that is the one that governs.
The tile calculator takes any dimensions you like and hands back the same list.