How many tiles for a 10x10 room?
A 10x10 floor in 12" tile takes 121 tiles, not the 100 the arithmetic suggests — grout joints and edge cuts add a whole row each way. Counts by room and tile size.
A 10' × 10' floor in 12" tile takes 121 tiles, or 134 with 10% for breakage and cuts.
That is 15 boxes at 9 to a box. The grid comes out 9 full tiles across with a 5 1/16" cut at each edge.
How that is worked out
- Each tile occupies its own size plus a grout joint: 12" + 3/16" = 12 3/16" of floor.
- Across 120" that gives 9 full tiles and a cut tile at each edge, because a centred layout splits the leftover between both sides rather than piling it on one.
- A cut tile still costs a whole tile, so the count is the full grid: 121 — noticeably more than the 100 that dividing the floor area by the tile area suggests. The 10% on top covers breakage, bad cuts and the ones with a chipped corner in the box.
Tiles needed, centred layout, 3/16" grout, 10% waste
| Room | Coverage | 12" tile | 18" tile | 6" tile | Boxes (12", 9/box) |
|---|---|---|---|---|---|
| 8' × 8' | 64 ft² | 90 | 54 | 318 | 10 |
| 10' × 10' | 100 ft² | 134 | 54 | 486 | 15 |
| 12' × 12' | 144 ft² | 186 | 90 | 688 | 21 |
| 14' × 14' | 196 ft² | 248 | 134 | 926 | 28 |
| 16' × 16' | 256 ft² | 318 | 134 | 1058 | 36 |
Worth knowing
- 10% waste is the figure for a straight layout in a square room. A diagonal layout wants 15%, and a room full of jogs and alcoves wants more again, because every jog is another cut tile.
- Buy the extra in the same order. Tile is made in batches and the shade varies between them — a box bought six months later to fix a cracked tile will not match, and there is no fixing that afterwards.
- Where the cut tiles land is a design decision, not just arithmetic. A centred layout gives equal cuts at both walls; starting full against the most visible wall puts the whole remainder at the other. Neither is wrong, but decide before you spread any thinset.
- The grout joint is part of the layout, not an afterthought. Over a ten-foot run, 3/16" joints add up to most of a tile's width — which is exactly the sort of thing that turns a layout that worked on paper into one that leaves a sliver at the far wall.
Work out your own numbers
- Tile layout
Full tiles across the middle and a sized cut tile at every edge, centred or started from one wall.
- Flooring and decking layout
How many rows, how wide to rip the first one, and where the end joints fall so they never line up.
Related questions
- How many 12x12 tiles do I need for a 100 square foot room?
- 121, and buy 134. The 100 that 100 ÷ 1 suggests is the trap: with 3/16" grout a 12" tile occupies 12 3/16" of floor, so only nine full tiles fit across a ten-foot run and a cut tile lands at each edge — eleven tiles per row either way. Every one of those cut tiles still costs a whole tile, and the 10% on top covers breakage. Order it all at once so it is from the same batch.
- How much extra tile should I buy?
- 10% for a straight layout in a simple room, 15% for a diagonal, and more if the room has alcoves, jogs or a lot of edges. If the tile is being discontinued or is hard to get, buy a whole extra box beyond that and put it in the loft — a replacement for a cracked tile in five years has to come from somewhere.
- Should I start tiling from the centre or the wall?
- From the centre, usually. It gives equal cuts at both walls, which looks deliberate, and it keeps a sliver from appearing along the most visible edge. Snap your layout lines and dry-lay a row both ways before you mix anything — if centring leaves an awkward cut, shifting the whole grid half a tile often fixes it.