Tile Adhesive Calculator - How Many Bags Do You Need? (UK)
Pop in your tiling area and how you're laying, and we'll tell you roughly how many 20kg bags of adhesive to order.
Interested? Then → Quotato for Tilers · More advice on the Blog & Chips guides.
How to use this calculator
Enter the area you're tiling in square metres, then choose the bed type - thin bed for walls, standard for most floors, or thick bed for large-format tiles. We convert that into the number of 20kg bags to buy.
How we calculate this
- Adhesive needed (kg) = area (m²) × coverage rate (kg/m²).
- Coverage rates: walls/thin bed 3.5 kg/m², floors/standard bed 5 kg/m², large format/thick bed 8 kg/m².
- Bags = kg ÷ 20, rounded up to the next whole 20kg bag, which builds in a little spare.
Worked example
Tiling a 10 m² floor with standard-bed tiles: 10 × 5 = 50 kg. Divide by 20kg per bag and you get 2.5, which rounds up to 3 bags.
UK notes & gotchas
- Coverage varies by trowel notch size and tile flatness - deeper notches and uneven backgrounds use more.
- Large-format tiles need a thicker bed and often back-buttering, so use the thick-bed setting.
- Always go by the manufacturer's stated coverage on the bag where it differs.
FAQ
Which bed type should I pick?
Thin bed for wall tiles, standard bed for most floor tiles, thick bed for large-format tiles or uneven backgrounds.
Does it include wastage?
Rounding up to whole 20kg bags gives a small buffer; for cut-heavy rooms keep an extra bag in hand.
How much area does a 20kg bag cover?
Roughly 4 m² on a thin or standard bed, or about 2.5 m² on a thick bed - it depends on trowel and tile size.