How Many Tiles Do I Need?
For standard 12x12in tile with a 1/8in grout joint in a straight layout, each tile effectively covers about 1.02 sq ft of floor once its grout joint is included — so add 10% waste to your room's area and divide by 1.02. For a different tile size, grout width, diagonal layout, or box count, the tile calculator handles those directly. This page is a quick reference table by room size, plus a worked example for a floor with a separate border or accent strip.
Tiles and boxes by room size
These figures assume 12x12in tile, a 1/8in grout joint, a straight (grid) layout at 10% waste, and boxes of 10 tiles — adjust proportionally if your box size differs.
| Room area | Tiles needed | Boxes (10/box) |
|---|---|---|
| 50 sq ft | 54 tiles | 6 boxes |
| 100 sq ft | 108 tiles | 11 boxes |
| 150 sq ft | 162 tiles | 17 boxes |
| 200 sq ft | 216 tiles | 22 boxes |
| 300 sq ft | 324 tiles | 33 boxes |
Daltile FAQ: buy about 10% more tile than you expect to need (a general recommendation, not layout-specific) — a diagonal or patterned layout uses 15% waste instead of 10% (a BuildyWork planning default with no external source), which raises every figure in this table by a few tiles; the calculator switches between the two directly.
A full example: field tile plus a border strip
A bathroom floor mixes two tile sizes: an 80 sq ft field area in 12x12in tile, bordered by a 20 linear ft, 4in-wide accent strip in a smaller 4x12in tile. These need two separate calculations, not one blended average — combining them would misestimate both, since the border's cut ratio is nothing like the field's. Field tile: 80 sq ft plus 10% waste = 88 sq ft, ÷ 1.02 sq ft per tile ≈ 87 tiles, or 9 boxes of 10. Border tile: the 20 ft × 4in strip is about 6.7 sq ft of area; each 4x12in accent tile with its grout joint covers roughly 0.35 sq ft, and a border needs the higher 15% pattern-cut waste since almost every piece meets a corner or a field-tile edge — 6.7 × 1.15 ≈ 7.7 sq ft, ÷ 0.35 ≈ 23 tiles, or 3 boxes if sold 8 to a box. The shopping list is two separate line items — 9 boxes of field tile and 3 boxes of border tile — not one combined order sized off an averaged area.
Tiles per 100 sq ft for other tile sizes
The table above is for 12x12in tile only. Tile size changes the count far more than anything else, so here is the same 100 sq ft of floor across common sizes. Each tile's footprint includes half a 1/8in joint on every side, and the figures are before waste. Add 10% (straight) or 15% (diagonal) and round up.
| Tile size | Footprint per tile | Tiles per 100 sq ft, before waste |
|---|---|---|
| 6x6in | 0.26 sq ft | 384 |
| 12x12in | 1.02 sq ft | 98 |
| 12x24in | 2.03 sq ft | 50 |
| 18x18in | 2.28 sq ft | 44 |
| 24x24in | 4.04 sq ft | 25 |
Grout joints matter more as tiles get smaller. A 6x6in tile gives up about 4% of its footprint to the joint at 1/8in, and a 24x24in tile about 1%, which is why small tiles pack in fewer per square foot than their face size suggests. Check the actual dimensions printed on the box too. Some tile sold as "12x12" is made to a metric size and measures slightly under 12 in, which adds tiles over a large floor.
Where the cuts land changes the waste, not the count
Most rooms are not an exact number of tiles wide, and how you set out the first row decides what the edge pieces look like. Take a floor 10 ft 3 in (123 in) across, with 12in tile on a 1/8in joint. Each tile plus joint takes 12.125 in, so the width is about 10.1 tiles. Starting against one wall gives 10 full tiles and a thin strip of under 2 in at the far wall. Thin strips like that are hard to cut and tend to crack or come loose. Centering the layout instead gives 9 full tiles with a piece of about 7 in at each wall.
Both layouts use 11 tiles per row, so the count is the same. The difference is in offcuts. A tile cut down to 7 in leaves a 5 in offcut, too small for the next 7 in edge piece, so every edge piece in the centered layout costs one full tile. A thin strip leaves a large offcut that can sometimes be used elsewhere. This is why the waste allowance exists: it pays for a better-looking layout. If you plan an unusual layout, such as centering on a doorway or a feature wall, dry-lay one row across the room before ordering the last boxes.
Measuring a room for tile
Measure the floor where the tile will actually go. That usually means wall to wall with the baseboards removed, since tile runs under the baseboard line, but not under fixed cabinets or a vanity that stays in place. A toilet sits on top of the tile, so its footprint is normally tiled and should stay in the area. Closets with a door count separately if they get the same tile. Where the floor meets a hallway or another room, decide where the transition sits before measuring, because that line sets the room's real length. Measure to the nearest inch, then convert to square feet once, at the end, rather than rounding each dimension to the nearest foot along the way.