How Much Subway Tile for a 30 Square Foot Backsplash?
Tiles needed
268 tiles
30 square feet, 3 by 6 subway tile, a sixteenth inch joint, 44 tiles a box, 15 percent waste.
A joint under an eighth of an inch only works with rectified tile, where the edges were cut after firing. Pressed tile varies enough in size that a tight joint leaves the run visibly out of line by the far wall.
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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 tile30 sq ft
- Tile width3 in
- Tile length6 in
- Tile thickness0.25 in
- Grout joint0.0625 in
- Tiles per box44 each
- Waste allowance15 %
Tiles needed268 tiles
A joint under an eighth of an inch only works with rectified tile, where the edges were cut after firing. Pressed tile varies enough in size that a tight joint leaves the run visibly out of line by the far wall.
| Area with 15% waste | 34.5 sq ft |
|---|---|
| Coverage of one tile | 0.129 sq fttile plus one joint |
| Tiles per square foot | 7.76 |
| Boxes at 44 per box | 7 |
| Thinset, 50 lb bags | 1about 85 sq ft per bag at this tile size |
| Grout | 2 lbsold in 10 and 25 lb boxes |
| Backer board, 3 by 5 sheets | 2 |
The material list this produces
| Tile, boxes | 7 |
|---|---|
| Thinset mortar, 50 lb bags | 1 |
| Grout, lb | 3 |
| Tile spacers, each | 536 |
| Cement backer board, 3 x 5 sheets | 2 |
| Backer board screws, each | 80 |
Waste allowance compared
Waste follows the layout: ten percent for a straight lay, fifteen for a diagonal or a cut up bathroom, twenty for herringbone.
| Waste allowance | Tiles needed | Boxes at 44 per box |
|---|---|---|
| 5% | 245 tiles | 6 |
| 10% | 256 tiles | 6 |
| 15% | 268 tiles | 7 |
| 20% | 280 tiles | 7 |
What else matters here
A run of counter 15 feet long with two feet of wall above it is 30 square feet. In 3 by 6 subway that is 268 tiles, because a small tile is a lot of tiles: 7.76 of them per square foot once the joint is counted.
A joint under an eighth of an inch only works with rectified tile, where the edges were cut after firing. Pressed tile varies enough in size that a tight joint leaves the run visibly out of line by the far end.
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 3x6 subway tiles per square foot?
About 7.76 at a sixteenth inch joint, or 7.5 at an eighth. The bare arithmetic of 3 by 6 is 8 per square foot, and the joint is what takes it below that.
What size grout joint for subway tile?
A joint under an eighth of an inch only works with rectified tile, where the edges were cut after firing.
How much waste should I add?
Ten percent for a straight lay in a square room, fifteen for a diagonal or a cut up bathroom, twenty for herringbone. Under ten leaves nothing for a bad box or a broken tile, and both happen.
The tile calculator takes any dimensions you like and hands back the same list.