How Much Tile Do I Need for a Bathroom Floor?
Quick answer: length × width of the floor minus the vanity and toilet footprints, plus 10% waste. A 5×8 bathroom is 40 sq ft, so you need about 44 sq ft — roughly 44–45 of 12×12 tiles or 15–16 of 12×24 tiles.
- The bathroom floor formula
- Subtract the fixtures
- Tile sizes for small baths
- Worked example: 5×8 bathroom
- Waste and common mistakes
- FAQ
The bathroom floor formula
Bathroom floors are the same area math as any room: length × width. A 5×8 bathroom is 40 sq ft. Then subtract anything that stays put — the vanity and toilet — and add 10% waste. The result is the square footage you order, or divide by the tile's coverage per box.
Subtract the fixtures
If the vanity and toilet stay in place, you don't tile under them — subtract their footprints, typically 6–10 sq ft for a standard vanity and a few square feet for the toilet base. If you're moving the vanity, tiling before it goes in, or want a continuous floor that can be re-floored later, count the full floor and buy the extra.
Tile sizes for small baths
In a small bathroom, larger tile means fewer grout lines — 12×24 or 18×18 makes the space look bigger and is easier to clean. 12×12 is the DIY classic. Small mosaics look great on shower floors but add a lot of grout lines on a bathroom floor. Whatever you choose, match the tile to a floor that isn't perfectly flat: small tiles hug uneven subfloors better.
| Tile size | Tiles per sq ft | 44 sq ft needs |
|---|---|---|
| 12×12 in | 1 | 44–45 |
| 12×24 in | 0.5 | 15–16 (boxed ~11 sq ft) |
| 18×18 in | 0.44 | 20 |
| 6×24 plank | 1 | 44 |
Worked example: a 5×8 bathroom
- Floor = 5 × 8 = 40 sq ft
- Minus vanity (8 sq ft) = 32 sq ft (if vanity stays)
- Add 10% = 35 sq ft → 35–36 of 12×12 tiles
- Full-floor version: 40 + 10% = 44 sq ft → 44–45 tiles
Waste and common mistakes
- Cutting around the toilet flange. The flange cut wastes a tile or two — that's part of the 10%.
- Forgetting the threshold. Door thresholds and step-downs need tile or a transition piece; count them or buy a matching threshold.
- Diagonal layouts in small rooms. Diagonals waste 15–20%. In a 5×8 bath, that's 1–2 extra tiles.
- Buying the exact count. Tile batches vary in shade — buy the waste up front and return unopened boxes.
FAQ
Measure length × width of the floor, subtract the vanity and toilet footprints if you're not tiling under them, and add 10% waste. A 5×8 bathroom floor is 40 sq ft, so you need about 44 sq ft.
About 44 sq ft of tile for a 5×8 bathroom floor (40 sq ft + 10% waste). That's roughly 44–45 of 12×12 tiles, 15–16 of 12×24 tiles, or 20 of 18×18 tiles.
Use 12×24 or 18×18 tile in small bathrooms — larger tiles mean fewer grout lines, which makes a small space look bigger and is easier to clean. 12×12 is a solid classic for DIY.
Add 10% for a straight layout in a simple rectangular bathroom. Add 15% if the floor is L-shaped, has a diagonal layout, or uses large-format tile.
Yes — if the vanity and toilet stay in place, you don't tile under them, so subtract their footprints (about 6–10 sq ft for a standard vanity).