How to use this calculator
- 1Measure the bathroom floor: length and width, or the area and the length of all the walls. Take off a shower tray or vanity unit that won't be tiled.
- 2Pick the floor tile size and joint. Bathroom floors often use 300 × 300 mm (12 × 12 in) or 300 × 600 mm tiles; smaller tiles grip better when wet.
- 3Choose how high the walls are tiled: 2.1 m (7 ft), half height, or type the height up to the ceiling.
- 4Check the door and window sizes, and take off wall areas that won't be tiled, such as behind a mirror or a bath panel.
- 5Pick the wall tile size, then add the tiles per box (or area per box) and prices to see boxes and cost.
The formula
- 01Floor tiles = (floor area − area not tiled) ÷ ((tile L + joint) × (tile W + joint)) × (1 + spare %), rounded up
- 02Wall area = length of all the walls × tiled height − door (up to the tiled height) − windows − areas not tiled
- 03Wall tiles = wall area ÷ ((wall tile L + joint) × (wall tile W + joint)) × (1 + spare %), rounded up
- 04Boxes = tiles ÷ tiles per box, rounded up (or by the area printed on the box)
- 05Adhesive ≈ area × rate for the tile size × 1.1 · Grout ≈ joint volume × 1.6 kg/L × 1.1
A bathroom is two jobs in one: the floor and the walls usually take different tiles, so each gets its own count and boxes. The walls are measured from the floor up, all the way round, and the door is taken off only up to the tiled height.
Wall tiles are counted on the net wall area, after the door, window and any area that won't be tiled. Because bathrooms have many cuts round pipes, corners and niches, 10 % spare is a minimum; add more for a small room with a niche or a boxed-in pipe.
The adhesive and grout are rough figures from the same rules as our tile adhesive and grout calculators, so you know roughly how many bags to add to the order.
Worked example
For a bathroom of 8 ft × 6 ft, the floor is 48 ft²: with 12 in × 12 in tiles that is 52 tiles, or 6 boxes of 10.
Tiling the walls to 7 ft, less a 36 in door and a 24 in × 24 in window, leaves 171 ft² of wall: 94 tiles of 24 in × 12 in, or 12 boxes of 8.
Add about 361 lb of tile adhesive (8 bags of 50 lb) and 7.7 lb of grout.
Tips before you buy
- Waterproof the shower area and the floor before tiling; the tiles and grout alone are not waterproof.
- Choose floor tiles with a slip-resistant (matt or textured) finish for a wet bathroom floor.
- Plan the layout so cut tiles end up in the least visible places — behind the door and at the bottom row of the walls.
- Slope the floor towards the drain; ask your tiler to check the fall before the tiles go down.
- Keep one box of each tile as spare for repairs: a cracked tile is easy to replace if the batch still matches.
Frequently asked questions
How many tiles do I need for a bathroom?
For a small 8 × 6 ft (2.4 × 1.8 m) bathroom tiled to 7 ft, about 52 floor tiles of 12 × 12 in and 94 wall tiles of 24 × 12 in, with 10 % spare and one door and window taken off. Enter your own sizes above: the floor and the walls are counted separately.
How high should bathroom wall tiles go?
In Pakistan and India 7 ft (2.1 m) or full height is usual. In the UK and much of Europe half height (about 1.2 m) with full height round the shower is common. Choose the height in the calculator or type your own.
Do I take the door and window off the wall area?
Yes. The door is taken off up to the tiled height, and a window only for the part inside the tiled height. The calculator does both; set the window count to 0 if there is none.
What size tiles are best for a small bathroom?
Larger wall tiles (such as 300 × 600 mm) mean fewer grout lines and make a small room look bigger; on the floor, smaller or textured tiles are less slippery when wet. Whatever the size, the calculator counts the tiles and boxes for it.
How much tile adhesive and grout does a bathroom need?
The results show a first estimate for your room. As a rule, 3–5 kg of cement-based adhesive per m² for tiles up to 450 mm (18 in), more for large tiles, and a few kg of grout for a whole bathroom. Use the tile adhesive and grout calculators for exact figures.
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Sources
- Tile counts: the same method as our tile calculator (tile + joint footprint, 10 % spare) — see its page for the formula and tests.
- Bathroom wall tile heights: 7 ft or full height in Pakistan and India (H & R Johnson); half height with full height round the shower in the UK and Europe (Marazzi).
- Adhesive rates by trowel notch: LATICRETE 254 Platinum data sheet
Formulas last reviewed: September 30, 2026 ·How we check our formulas