How to use this calculator
- Enter the area you are tiling.
- Choose the trowel notch your tile size needs (larger tiles need a bigger notch).
- If your adhesive bag gives a usage rate, type it in to replace ours.
The formula
Adhesive = rate × area × (1 + extra %)
Bags = adhesive ÷ bag size, rounded up
A bigger notch leaves thicker ridges of adhesive, so it uses more per square metre. Our defaults (2–6 kg/m² from 4 mm to 12 mm notches) sit within the ranges adhesive makers publish for common trowels.
Worked example
3 m × 2 m with a 6 mm notch at 3 kg/m² plus 10% extra needs 19.8 kg.
That's 1 bags of 20 kg.
Tips before you buy
- Check coverage by lifting a freshly laid tile: the back should be well covered (most guidance asks for near-full coverage on floors and in wet areas).
- Use flexible (S1) adhesive on wooden floors, underfloor heating and large-format tiles.
- Don't mix more than you can use within the pot life on the bag.
Frequently asked questions
›How much tile adhesive per m²?
Typically 2–6 kg/m² depending on the notch size, tile and surface. Large or textured tiles can need more.
›Which trowel notch should I use?
Roughly: small wall tiles 6 mm, medium floor tiles 8–10 mm, large tiles 10–12 mm. The tile and adhesive makers' guidance comes first.
Sources
Formulas last reviewed: September 29, 2026. How we check our formulas