Grout (fuga) is easy to under- or over-buy. The amount depends on joint width, tile format, and net tiled area — not on a random “one bag per bathroom.”
Worked idea
A floor 4.0 × 3.0 m (12 m²) with 600×600 mm tiles and a 3 mm joint needs far less grout than the same floor with 300×300 mm tiles and a 5 mm joint. Smaller tiles mean more joint length per square metre.
Steps
- Enter room size, tile size, and joint width in the tiling planner.
- Subtract openings so the area is net.
- Read grout (and adhesive) on the material list.
- Round up to whole packs of the brand you will use; check kg/m² or bags on the label.
If you change joint width from 2 mm to 4 mm, re-run the list before you shop — the grout line moves more than people expect.
Adhesive is covered in tile adhesive calculation.
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