Tile Calculator - Count, Coverage, Grout and Adhesive
Work out exactly how many tiles you need for any room, floor or wall, plus the grout, adhesive, spacers and wastage for your tile size and laying pattern. Handles straight lay, diagonal, herringbone and offset with real waste factors.
Advanced options
Total Tiles Needed
Full Material Breakdown
| Material | Quantity | Notes |
|---|
Recommended Spacer and Grout Specification
| Item | Recommendation |
|---|
Use Tile Calculator for Floors, Walls and Any Laying Pattern
Enter the area or room dimensions, choose your tile size and pattern, and the calculator returns tiles needed, boxes to buy, grout, adhesive and spacers - with the correct waste factor built in.
Tile Sizes, Joint Widths and Typical Uses
Every tile size has a recommended grout joint width and works best on certain surfaces. This reference table shows the standard recommendations.
| Tile size | Recommended joint | Best for | Tiles per m² |
|---|---|---|---|
| 100 x 100 mm | 2 - 3 mm | Splashbacks, mosaic panels | 100 |
| 150 x 150 mm | 2 - 3 mm | Bathrooms, small walls | 44.4 |
| 200 x 200 mm | 3 mm | Bathroom floors, kitchen walls | 25 |
| 300 x 300 mm | 3 mm | Standard floors, walls | 11.1 |
| 300 x 600 mm | 3 mm | Modern wall tiles | 5.5 |
| 400 x 400 mm | 3 mm | Living areas, kitchens | 6.25 |
| 450 x 450 mm | 3 mm | Large floors | 4.9 |
| 600 x 600 mm | 3 - 4 mm | Open plan floors | 2.8 |
| 600 x 1200 mm | 3 - 4 mm | Large format floors | 1.4 |
| 800 x 800 mm | 4 - 5 mm | Premium floors, commercial | 1.6 |
| 1000 x 1000 mm | 5 mm | Commercial, luxury homes | 1 |
Waste Factor by Laying Pattern
The pattern you choose changes the amount of waste. Intricate patterns need more tiles. These are the industry-standard waste allowances.
| Pattern | Waste factor | Notes |
|---|---|---|
| Straight lay (grid) | 5 - 8% | Simplest, least waste |
| Offset / brick bond | 8 - 12% | Extra cuts at edges |
| Diagonal / diamond | 12 - 15% | 45 degree cuts increase waste |
| Herringbone | 15 - 20% | High number of cuts |
| Chevron | 15 - 20% | Angled tile edges |
| Basketweave | 12 - 18% | Complex layout |
| Mosaic sheet | 5 - 10% | Smaller pieces, careful cutting |
Tile Adhesive and Grout Coverage Guide
How far does a bag of adhesive or grout go? These are the standard coverage rates per kg and per 20 kg bag.
| Product | Coverage per kg | Coverage per 20 kg bag | Notes |
|---|---|---|---|
| Standard tile adhesive | 0.25 - 0.35 m² | 5 - 7 m² | 3 - 4 mm bed, small tiles |
| Large format adhesive | 0.15 - 0.25 m² | 3 - 5 m² | 6 - 10 mm bed, backing butter |
| Wall tile adhesive | 0.3 - 0.4 m² | 6 - 8 m² | 3 mm notch trowel |
| Floor tile adhesive | 0.2 - 0.3 m² | 4 - 6 m² | 6 mm notch trowel |
| Stone tile adhesive | 0.15 - 0.2 m² | 3 - 4 m² | 10 mm notch trowel, back butter |
| Cement-based grout | 0.5 - 1 kg per m² | 20 - 40 m² | Depends on joint size |
| Epoxy grout | 1 - 1.5 kg per m² | 13 - 20 m² | Wet areas, high traffic |
How the Tile Calculator Works
Every number on this page uses the standard materials estimation method that tilers and quantity surveyors apply. Here is the exact process.
- Net area is calculated from your dimensions minus openings, or entered directly.
- Waste factor is applied based on the laying pattern you choose - diagonal and herringbone need significantly more tiles than straight lay.
- Tiles per square metre are computed from the tile size including grout joints.
- Total tiles = net area x tiles per m² x (1 + waste).
- Boxes to buy = total tiles rounded up to the nearest full box.
- Grout volume is calculated from tile dimensions, joint width and tile thickness - the standard formula used by grout manufacturers.
- Adhesive quantity is derived from tile size and bed thickness, using coverage rates from adhesive manufacturers.
- Spacer size is matched to your tile type - rectified porcelain uses 1-2 mm, ceramic uses 3 mm, natural stone uses 5 mm.
Tile, Grout and Adhesive Formulas
These are the exact formulas used by the calculator. Bookmark this section if you want to verify the numbers yourself.
- Net area = length x width - openings
- Tiles per m² = 1 / ((tile W + joint) x (tile H + joint))
- Total tiles = net area x tiles per m² x (1 + waste)
- Boxes = ceil(total tiles / tiles per box)
- Grout (kg/m²) = ((tile W + tile H) / (tile W x tile H)) x joint x tile thickness x density
- Adhesive (kg/m²) = area x bed thickness x density / 1000
- Spacers per m² = tiles per m² x 2 (approximately)
Worked example: A 5 m x 3 m floor with 300 x 300 mm tiles, 3 mm joint, straight lay. Net area = 15 m². Tiles per m² = 1 / (0.303 x 0.303) = 10.9. Total tiles before waste = 163. With 10% waste = 180 tiles. If 11 tiles per box = 17 boxes. Grout = 0.5 kg/m² x 15 = 7.5 kg. Adhesive = 3.5 kg/m² x 15 = 52.5 kg (3 bags of 20 kg).
Frequently Asked Questions About Tile Calculation
How many tiles do I need for a 5 m x 3 m room?
It depends on the tile size. For 300 x 300 mm tiles, you need about 180 tiles (including 10% waste). For 600 x 600 mm tiles, that drops to about 45 tiles. For 200 x 200 mm tiles, it rises to 410 tiles. The calculator above gives the exact number for any tile size and pattern.
How much wastage should I allow for tiles?
Standard waste for a straight lay is 5 - 10%. Increase to 12 - 15% for diagonal and 15 - 20% for herringbone. Add another 5% if you're a DIY installer, if the room has lots of corners, or if the tile is a discontinued line you might not be able to match later. The calculator has a pattern-based waste table you can override.
How many tiles are in a box?
It varies by manufacturer and tile size. Common box sizes: 300 x 300 mm typically has 11 - 17 tiles per box. 600 x 600 mm has 4 tiles per box. 200 x 200 mm has 25 tiles per box. Always check the label - the calculator lets you enter the exact tiles-per-box from your chosen product.
How much grout do I need per square metre?
It depends on tile size, joint width and tile thickness. As a rough guide: large tiles (600 x 600 mm) with 3 mm joints use about 0.3 - 0.5 kg/m². Small tiles (100 x 100 mm) with 3 mm joints use about 1.5 - 2 kg/m². Wider joints increase consumption. The calculator gives the exact grout weight for your tile and joint combination.
How much tile adhesive do I need?
Coverage depends on the trowel notch size and tile type. For standard wall tiles with a 3 mm notch, one 20 kg bag covers 6 - 8 m². For large format floor tiles with a 10 mm notch, one bag covers only 3 - 4 m². Always use a notched trowel that matches your tile size, and back-butter large tiles for full coverage.
What is the best grout joint width for my tiles?
For rectified porcelain, use 1 - 2 mm. For standard porcelain, use 2 - 3 mm. For ceramic, use 3 mm. For natural stone, use 5 mm or more. For rustic or quarry tiles, use 10 mm. Wider joints tolerate size variation; narrower joints need precision-made tiles.
How many spacers do I need?
As a rule of thumb, plan for 2 spacers per tile intersection. For 300 x 300 mm tiles covering 15 m², that is roughly 2 x 165 tiles = 330 spacers. Buy in packs of 200 or 500. The calculator outputs the exact count based on your tile size and area.
How do I calculate diagonal tile waste?
Diagonal laying requires 12 - 15% waste compared to 5 - 10% for straight lay. The extra waste comes from the triangular cuts at the perimeter. Adding 15% is a safe figure for most rooms; add more if the walls are out of square or the room has many corners. The calculator applies the correct factor automatically when you select diagonal.
Can I use the same tiles for floor and wall?
Yes, if the tile is rated for both. Check the PEI rating (Porcelain Enamel Institute) - PEI 3 is suitable for residential floors and walls, PEI 4 for commercial floors, PEI 5 for heavy traffic. Wall-only tiles (PEI 0) should never be used on floors. The calculator works the same for both.
How thick should tile adhesive be?
For wall tiles up to 300 x 300 mm, use a 3 - 6 mm notched trowel. For floor tiles up to 400 x 400 mm, use 6 - 8 mm. For large format tiles 600 x 600 mm and above, use 10 - 12 mm and back-butter each tile. The thickness of the adhesive after the tile is pressed down should be about 3 mm for walls and 5 - 6 mm for floors.
Do I need to seal tiles after installation?
Porcelain and ceramic tiles do not need sealing - they are non-porous. Natural stone tiles (marble, travertine, slate) do need sealing before and after grouting. Grout itself should be sealed on floors and in wet areas to prevent staining, unless you use epoxy grout which does not require sealing.
How long after tiling can I walk on the floor?
Light foot traffic is usually fine 24 hours after tiling with standard cement-based adhesive. Full cure takes 7 days. For heavy traffic or furniture, wait the full 7 days. For epoxy adhesive or rapid-set products, follow the manufacturer's guidelines - some allow traffic after just 4 - 6 hours.
What is the difference between ceramic and porcelain tiles?
Ceramic tiles are made from clay and are softer - they chip more easily but are easier to cut. Porcelain tiles are made from denser clay fired at higher temperatures - harder, less porous and more durable. Porcelain is the better choice for floors, wet areas and high-traffic spaces. Ceramic is fine for walls and light-use floors.
Should I buy all my tiles at once?
Yes, always. Tile dye lots vary between batches, so tiles bought at different times may not match exactly. Buy everything you need in one order, plus 10% extra for future repairs. Store the spare tiles in a dry place - if a tile cracks years later, you will have a matching replacement.
References & Standards
- ISO 13006 - Ceramic tiles: Definitions, classification, characteristics and marking
- ANSI A137.1 - American National Standard Specifications for Ceramic Tile
- BS EN 14411 - Ceramic tiles: Definition, classification, characteristics
- TCNA Handbook for Ceramic, Glass and Stone Tile Installation
- BS 5385 - Wall and floor tiling - Code of practice
- IS 15622 - Ceramic tiles specification (India)
- AS 3958.1 - Ceramic tiles - Guide to the installation of ceramic tiles (Australia)
- NIS 550 - Nigerian Industrial Standard Building Code