The Bathroom Tile Calculator works out how many tiles you need for a bathroom floor and for tiled walls. The floor tab subtracts areas you won’t tile (vanity or tub footprint) and gives tiles and boxes; the walls tab takes the length of tiled walls and the tile height, minus openings and fixtures.
Bathroom Tile Calculator
Floor and wall tiles for a bathroom — tiles and boxes for any tile size, with waste.
It works with any tile size — 12 × 12 in floor tiles, 3 × 6 in subway tiles or large-format tiles. For the shower itself, the Shower Tile Calculator is linked below.
Formula
Floor: Tiles = ⌈(L × W − untiled) ÷ tile area × (1 + waste)⌉; boxes = ⌈tiles ÷ tiles per box⌉
Walls: Tiles = ⌈(wall length × tile height − openings) ÷ tile area × (1 + waste)⌉
Tile area in ft² = tile width (in) × tile length (in) ÷ 144.
How the Calculation Works
Step 1: Work out the area to be tiled — floor minus fixtures, or wall run × height minus openings.
Step 2: Divide by the area of one tile.
Step 3: Add waste and round up; for floors, convert to boxes.
Variables Explained
| Input | Meaning |
|---|---|
| Area not tiled | Vanity, built-in tub or cabinet footprint |
| Length of tiled walls | Total run of walls to tile, measured along the floor |
| Tile height on walls | Wainscot height or floor to ceiling |
| Openings / fixtures to skip | Doors, windows, mirror area not tiled |
Example Calculation
Floor
Given: 8 × 5 ft bathroom, 12 ft² untiled, 12 × 12 in tiles, 10% waste, 10 per box
Tiled area = 40 − 12 = 28 ft² → 28 × 1.10 = 30.8 → 31 tiles → 4 boxes
Walls
Given: 26 ft of wall tiled 4 ft high, 15 ft² skipped, 3 × 6 in subway tile, 10% waste
Tiled area = 26 × 4 − 15 = 89 ft²
Tile area = 18 ÷ 144 = 0.125 ft² → 89 ÷ 0.125 × 1.10 = 783.2 → 784 tiles
Waste Factor Considerations
The right allowance depends on the tile size, layout pattern (straight, diagonal, herringbone), number of cuts around fixtures and how many spares you want for future repairs. Large tiles in small bathrooms often produce more offcuts.
Material Estimation Notes
- Tile area is the physical surface; you still buy whole boxes.
- Trim pieces (bullnose, pencil liner) for the top of wainscot are counted separately by linear foot.
- Buy all tile from the same batch to avoid color variation.
Frequently Asked Questions
How many tiles do I need for a bathroom floor?
Floor area minus untiled areas, divided by one tile’s area, plus waste.
How do I calculate bathroom wall tile?
Length of tiled walls × tile height, minus openings, divided by tile area.
How many 3×6 subway tiles per square foot?
144 ÷ 18 = 8 tiles per ft², before grout joints and waste.
Should I tile under the vanity?
Freestanding vanities usually sit on tile; built-in cabinets often don’t — subtract only what won’t be tiled.
How many boxes of tile do I need?
Tiles ÷ tiles per box, rounded up.