the symbol ofStrengthFind my product →Choose your adhesive and enter the area — we’ll work out how much you need and how many packs to buy, using each product’s real coverage and pack size.
Pack size & coverage come from the product you pick. Not sure? Use the recommender.
▼This grade is supplied in one standard pack.
Bigger tiles need a deeper bed, which uses more adhesive per m². Match the notch to your tile.
▼Extra for spillage, cuts & uneven surfaces.
Coverage and pack size are taken from each product’s datasheet — e.g. the S-series covers ~45–50 sq.ft per 20 kg bag at a 3 mm bed, while Flexit 2K gives ~8–10 sq.ft per 4 kg bucket. Actual usage varies with substrate flatness, tile back-profile and technique. For large-format tiles use solid-bed (back-buttering) and allow ~15% wastage. Always confirm against the product datasheet.
This calculator converts your floor or wall area into tile adhesive bags using each SUMO product’s real datasheet coverage — 4.3 kg/m² at a 3 mm bed for the S-series — scaled by the bed thickness your tile size needs. No generic averages: the number you get is the number the datasheet supports.
Pick your adhesive grade — S01 to S04 or Flexit 2K. Not sure which? Use the Product Recommender first.
Enter the area to tile (or length × width) in sq.ft or m².
Choose the bed thickness. Small tiles lay on 3–6 mm; 600 mm+ formats need 10–15 mm with back-buttering.
Keep ~10% wastage (15% for large-format).
Read off kilograms and whole bags to buy.
Coverage is defined at a 3 mm bed in each product datasheet; the factors model how a deeper notch consumes more adhesive. Flexit 2K uses 4.78 kg/m² in 4 kg buckets.
| Bed thickness | Typical use | Coverage per 20 kg bag |
|---|---|---|
| 3 mm | Small ceramic, thin bed | ≈ 4.7 m² · 50 sq.ft |
| 6 mm | Tiles up to 150 mm | ≈ 4.2 m² · 45 sq.ft |
| 8 mm | 150–300 mm tiles | ≈ 3.5 m² · 38 sq.ft |
| 10 mm | 300–600 mm tiles | ≈ 3.0 m² · 32 sq.ft |
| 12 mm | 600 mm+ / floors | ≈ 2.4 m² · 26 sq.ft |
| 15 mm | Large format, back-buttered | ≈ 1.9 m² · 21 sq.ft |
| 20 mm | Heavy / uneven beds | ≈ 1.5 m² · 16 sq.ft |
This is why "how much does a 20 kg bag cover" has no single answer — the honest range is roughly 16–50 sq.ft, set almost entirely by bed thickness. Substrate flatness and tile back-profile move it further.
The datasheet number assumes a flat substrate and the right trowel. Four things quietly move real-world consumption away from it:
Substrate flatness — an undulating floor deepens the average bed without anyone deciding it. A 3 mm dip across the room adds a bag before you notice.
Back-buttering — the thin skim on the back of large-format tiles is real consumption; the calculator’s thicker bed factors include it, manual estimates usually forget it.
Tile back profile — deep waffle or button backs hold extra adhesive in the recesses compared to a flat back.
Comb-off and cuts — adhesive combed beyond the tile line at edges, doorways and cut pieces is scraped off and binned. This is most of the 10% wastage.
Level first, tile second — correcting a floor with adhesive is the most expensive levelling there is. A screed or self-levelling pass costs less per mm.
Match the notch to the tile, not to habit — a 10 mm notch under a 300 mm tile is a third of a bag wasted per room.
Mix whole bags where the area allows — part-bag mixes drift on water ratio and leave pot residue each time.
Lift the first tile you lay and check the back — full contact at the right bed depth means the estimate holds; voids mean the bed or technique needs fixing before the maths does.
120 sq.ft = 11.15 m² of floor.
600 mm tiles lay on a ~12 mm combined bed → factor 1.93.
11.15 × 4.3 × 1.93 ≈ 92.5 kg → + 10% wastage ≈ 102 kg.
102 ÷ 20 = 5.1 → round up.
At a 3 mm thin bed, a 20 kg bag of SUMO S-series covers about 45–50 sq.ft. At the 10–12 mm beds large vitrified tiles need, the same bag covers 26–32 sq.ft. Bed thickness — not brand — is what changes the answer.
Yes, roughly 1.5–2× more per sq.ft. 600 mm+ tiles need a 10–15 mm combined bed with back-buttering for full contact, versus 3–6 mm for small ceramic. The calculator applies the correct factor when you pick the bed.
The per-mm consumption is the same, but walls typically use thinner beds (3–6 mm with smaller tiles) while floors run 6–12 mm, so a bag goes further on walls in practice.
Keep 10% wastage for standard formats and 15% for large-format or diagonal layouts — that covers back-buttering, edge losses and the part-bag left in the last mix. The calculator has it built in.
S02 and above are formulated for tile-on-tile work (S02 is the "improved bond / tile-on-tile" grade). Consumption is the same 4.3 kg/m² at 3 mm, so bag counts don’t change with the grade.
As a guide: 3 mm for small ceramic, 6 mm up to 150 mm tiles, 8 mm for 150–300 mm, 10 mm for 300–600 mm, 12 mm+ for 600 mm and up or uneven floors. When in doubt between two, price the thicker one.