How many wall tiles do I need per m²?

It depends on tile size. For 300x600mm tiles you need approximately 5.6 tiles per m², for 250x400mm about 10 per m², and for 100x200mm metro tiles about 50 per m². Always add 10% for straight or brick bond patterns and 15% for herringbone to cover cuts and breakages.

What tile adhesive should I use for bathroom walls?

For bathroom walls, use a flexible powder adhesive (such as Weber or Mapei) rated C2 or higher. Flexible adhesive handles the moisture and temperature changes in bathrooms. For plasterboard substrates, a flexible powder adhesive is essential. Ready-mixed adhesive is only suitable for small ceramic tiles on dry walls. See our tile adhesive calculator (/tiling/tile-adhesive-calculator/) for exact quantities.

How wide should tile grout joints be?

For wall tiles, 2mm joints are standard in the UK. Metro tiles often look best with 1.5mm joints, while larger format tiles (300x600mm) can use 2-3mm joints. BS 5385-1 recommends minimum 2mm joints for most wall tiles. Narrower joints give a more contemporary look but are harder to fill evenly. Use our grout calculator (/tiling/grout-calculator/) for precise grout quantities.

Do I need to tile behind a bath?

You do not need to tile behind a bath panel, but you should tile at least one tile row above the bath rim to waterproof the splash zone. Building Regulations do not specifically require tiling, but best practice is to tile at least 300mm above any fitting where water may splash. Many tilers tile the full wall for a cleaner finish.

How much tile wastage should I allow?

Allow 10% waste for straight or brick bond laying patterns, and 15% for herringbone or diagonal patterns. Herringbone requires more cuts, especially at edges. If you have many obstacles (windows, niches, pipe boxings), consider adding an extra 5% on top. It is always better to have spare tiles than to run short mid-job.

Wall Tile Calculator — Tiles, Adhesive & Grout Needed

Calculate the number of wall tiles, adhesive bags and grout you need. Covers all standard UK tile sizes with waste allowances for different laying patterns.

Wall Height

Standard UK ceiling height is 2.4m

Wall Width

Width of each wall to tile

Number of Walls

Tile Size

Window Area to Subtract

Total window area across all walls

Door Area to Subtract

Standard UK door: ~1.76 m²

Laying Pattern

Joint Width

Include wastage allowance

Recommended: 10% for Straight (Grid) pattern

Wastage Percentage

Herringbone typically needs 15%, straight/brick bond 10%

Price Per Box (optional)

Adhesive Price/Bag (optional)

Grout Price/Bag (optional)

How We Calculate This

Our wall tile calculator works by calculating the total wall area to be tiled, subtracting any windows and doors, then dividing by the individual tile area. We add a waste allowance based on your chosen laying pattern and round up to complete boxes.

The formula

Tiles needed = (Net wall area ÷ Tile area) × (1 + Waste %)

For example, tiling 10 m² with 300×600mm tiles: 10 ÷ 0.18 = 56 tiles, plus 10% waste = 62 tiles. At 8 tiles per box, that's 8 boxes.

Adhesive and grout estimates

Adhesive: A standard 25kg bag of flexible powder adhesive covers approximately 4-5 m² of wall tiles using a 6mm notched trowel (as per manufacturer guidelines from Weber, Mapei, and BAL).
Grout: Calculated based on tile size, joint width, and tile thickness. A 5kg bag of grout typically covers 5-15 m² depending on these factors.

Laying patterns

Straight (Grid): 10% waste — simplest pattern with least cutting.
Brick Bond (Offset): 10% waste — tiles offset by half, like brickwork. Most popular for metro tiles.
Herringbone: 15% waste — tiles laid at 45° angles. More cuts required at all edges.

All calculations follow guidance from BS 5385-1 (wall tiling) and manufacturer coverage rates for adhesives and grouts commonly available in the UK (BAL, Weber, Mapei, Dunlop).

Frequently Asked Questions

Related Calculators

Tile Adhesive Calculator

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Grout Calculator

Calculate grout quantities based on tile size and joint width.

Shower Tray Fall Calculator

Calculate the correct fall gradient for a wet room or shower tray.

Bathroom Extraction Rate Calculator

Calculate the required extraction rate for bathroom ventilation.

Wet Room Tanking Calculator

Calculate tanking kit materials for wet room waterproofing.

Last updated: February 2026

All calculations are estimates. Verify with your supplier.