Tile Adhesive Calculator — Coverage, Bags & Class
Calculate exactly how many bags of tile adhesive you need for any tiling job. Enter your area and tile size to get coverage in kg/m², total weight and number of 20 kg bags — with adhesive class guidance (C1, C2 S1, C2 S2) for your application.
How the tile adhesive calculator works
- 1Coverage rate depends on tile size: ≤200 mm → 3.5 kg/m², 200–400 mm → 4.5 kg/m², >400 mm → 5.5 kg/m²
- 2Large format tiles (>600 mm) also require back-buttering — add 1–1.5 kg/m²
- 3Total adhesive = area (m²) × coverage rate (kg/m²)
- 4Bags needed = total kg ÷ bag weight (typically 20 kg or 25 kg), rounded up
- 5Add 5% for waste and end-of-bag losses
- 6Choose adhesive class: C1 (standard), C2 (improved), with deformability S1 or S2 for wet/heated areas
Worked example
Kitchen floor: 12 m². 300×300 mm ceramic tiles, straight lay. Standard dry area.
Coverage rate: 4.5 kg/m² (200–400 mm tile bracket). Total adhesive: 12 × 4.5 = 54 kg + 5% waste = 57 kg → 3 bags of 20 kg. Use C1 adhesive for a dry kitchen floor.
Frequently asked questions
What is the difference between C1 and C2 tile adhesive?
C1 (standard) has lower adhesive strength and is suitable for dry, stable substrates. C2 (improved) has higher bond strength and is required for large-format tiles, wet areas and heated floors. The S1/S2 designation adds deformability for flexible substrates.
How many m² does a 20 kg bag of tile adhesive cover?
For standard 300×300 mm tiles: approximately 4.4 m² per 20 kg bag (at 4.5 kg/m², 200–400 mm bracket). For large-format 600×600 mm tiles: approximately 3.6 m² per 20 kg bag (at 5.5 kg/m²). Coverage varies by trowel notch size and substrate absorption.
Can I use the same adhesive for floor and wall tiles?
C2 adhesive is suitable for both floors and walls. Standard C1 adhesive used on walls must have non-slip (T) designation to prevent tiles sliding before the adhesive cures. Check the product datasheet.
What trowel notch size for tile adhesive?
6×6 mm V-notch for small tiles (≤150 mm). 8×8 mm or 10×10 mm square notch for medium tiles (150–400 mm). 12×12 mm notch for large format tiles. Larger notches give more adhesive bed and better coverage.
How long does tile adhesive take to cure?
Standard cement-based adhesive: 24 hours before grouting in dry conditions, 48 hours in wet areas. Rapid-set adhesive: as little as 2–4 hours. Full structural strength is reached at 28 days. Do not expose to water or traffic before the minimum cure time.