# Bathroom Tile Calculator

> Calculate exactly how many tiles you need for your bathroom. Includes grout, adhesive, and waterproofing estimates for floors and walls.

Canonical: https://renoquant.com/bathroom-tile-calculator
Prices updated: 2026-03

## How to Calculate Tiles for a Bathroom

Bathroom tiling is one of the most impactful renovations you can make, but it requires careful planning. Bathrooms have unique requirements — waterproofing, slip resistance, and moisture-resistant grout — that set them apart from tiling other rooms.

### Bathroom Tile Calculation: Floor vs Walls

**Floor tiles:** Length × Width of the floor area, divided by the area of a single tile, plus waste.

**Wall tiles:** Calculate the area of each wall separately (height × length), subtract any windows, then divide by single tile area plus waste.

For a bathroom measuring 2.5m × 3m with 2.5m ceiling height:

| Surface | Area | 30×30cm Tiles Needed (incl. 10% waste) |
|---------|------|--------------------------------------|
| Floor | 7.5 m² | 92 tiles |
| All four walls | 27.5 m² | 337 tiles |
| Shower area only (3 walls, 2m high) | ~10 m² | 123 tiles |
| **Total (floor + full walls)** | **35 m²** | **429 tiles** |

### Choosing Bathroom Tiles by Area

Different bathroom zones have different requirements:

| Zone | Tile Requirement | Recommended Type |
|------|-----------------|-----------------|
| Shower floor | Slip-resistant (R11+), small format | Mosaic or 10×10cm with drainage slope |
| Shower walls | Waterproof, easy-clean | Large-format porcelain, minimal grout |
| Bathroom floor | Slip-resistant (R10+) | Porcelain, matte finish |
| General walls | Moisture-resistant | Ceramic or porcelain, any size |
| Vanity splashback | Easy-clean, decorative | Mosaic, subway tiles, feature tiles |

### Waterproofing: The Critical Step

Waterproofing is non-negotiable in bathrooms. Water that gets behind tiles causes mould, structural rot, and costly damage. Here's what you need:

- **Liquid membrane** — Apply 2 coats with a roller over the entire wet area. Coverage is approximately 1-1.5 L per m² for two coats.
- **Reinforcing tape** — Use in corners and at wall-floor junctions where movement and cracking are most likely.
- **Drying time** — Allow 24 hours for the membrane to fully cure before tiling over it.
- **Coverage area** — At minimum, waterproof the shower zone. Best practice is to waterproof the entire bathroom floor and all walls to at least 1.8m height.

### Materials List for Bathroom Tiling

| Material | Quantity per m² | Cost per m² |
|----------|----------------|------------|
| Porcelain tiles | 11-12 tiles (30×30cm) | €15-50 |
| Tile adhesive (flexible) | 4-5 kg | €3-5 |
| Anti-mould grout | 0.5-0.8 kg | €2-4 |
| Waterproofing membrane | 1-1.5 L | €5-8 |
| Silicone sealant | As needed for edges | €5-10 per tube |

### Floor Tiles vs Wall Tiles: Key Differences

Not all tiles are interchangeable between floors and walls:

- **Floor tiles** must have a slip rating (R9 minimum, R10-R11 preferred for wet areas). They're thicker (8-10mm) and made from denser porcelain.
- **Wall tiles** can be thinner ceramic (6-8mm) and don't need a slip rating. They're lighter, which prevents them pulling away from the wall under their own weight.
- **Floor tiles can go on walls** (if the wall structure supports the weight), but wall tiles should never go on floors.

### Grout for Bathrooms

Standard grout absorbs moisture and can grow mould. For bathrooms, always use:

- **Epoxy grout** — Completely waterproof and mould-resistant. More expensive (€8-15/kg) but lasts the life of the tiles.
- **Anti-mould cementitious grout** — A budget alternative (€3-5/kg) with fungicide additives. Effective but may need resealing every few years.
- **Silicone sealant** — Use in corners, edges, and where tiles meet the bathtub or shower tray. Grout cracks in these movement zones; silicone flexes.

### Common Bathroom Tiling Mistakes

- **Tiling before waterproofing** — The most costly mistake. Water finds every gap and causes hidden damage.
- **Using wall tiles on the floor** — They'll crack under foot traffic and lack slip resistance.
- **Grout in movement joints** — Where walls meet floors, use silicone sealant instead of grout.
- **Not planning tile layout** — Dry-lay tiles first to avoid thin slivers at edges. Centre your layout so cuts are even on both sides.

### When to Hire a Professional Tiler

Bathroom tiling is one renovation where professional skill truly matters. Waterproofing failures are invisible until water damage appears months later. Hire a professional if you're tiling a shower, working with large-format tiles (60cm+), or if you're not confident in your waterproofing technique.

## Frequently Asked Questions

### How many tiles do I need for a standard bathroom?

A standard bathroom floor (2.5×3m = 7.5 m²) requires about 92 tiles at 30×30cm, including 10% waste. Wall tiling varies — a fully tiled bathroom can need 3-4 times the floor tile quantity.

### What type of tile is best for bathroom floors?

Porcelain tiles with a slip-resistant finish (R10 or R11 rating) are the best choice for bathroom floors. They're waterproof, durable, and available in many styles. Avoid polished tiles — they're dangerously slippery when wet.

### Do I need to waterproof under bathroom tiles?

Absolutely. Waterproofing (tanking) is essential in wet areas — shower walls, shower floors, and around the bathtub. Use a liquid waterproofing membrane applied under the adhesive. Skipping this step risks water damage to your subfloor and walls.

### What size tiles work best in a small bathroom?

Medium-format tiles (30×60cm or 45×45cm) with minimal grout lines make small bathrooms appear larger. Avoid very small tiles (mosaics) on large areas as the many grout lines can make the space feel busy.

### Should I tile the floor or walls first?

Tile the walls first, stopping one row above the floor. Then tile the floor and finish with the bottom row of wall tiles overlapping the floor tiles. This ensures water runs down the wall tile onto the floor tile, not behind it.

### How much does it cost to tile a bathroom?

Materials for tiling a standard bathroom floor (7.5 m²) cost €150-400 depending on tile choice. Full bathroom tiling (floor + walls) typically costs €500-1500 in materials. Professional installation adds €30-50 per m².

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Interactive version with calculator: https://renoquant.com/bathroom-tile-calculator. Figures are estimates; final quotes vary by site conditions, materials, and region.