How much grout do I need? How to use the calculator
- 1Enter the tiled area.
- 2Enter the tile size, its thickness and the joint width.
- 3Keep the density at 1.6 kg/L unless your grout bag says otherwise.
How to calculate grout (formula)
- 01Grout per m² = ((A + B) ÷ (A × B)) × C × D × density
- 02A, B = tile length and width (mm) · C = tile thickness (mm) · D = joint width (mm)
- 03Total = grout per m² × area × (1 + extra %)
(A + B) ÷ (A × B) is the length of joint in each square metre. Multiply by the joint's depth and width to get its volume in litres per m², then by the grout's density to get kilograms.
This is why 5 cm mosaics need several times more grout than 60 cm tiles: there is much more joint per square metre.
Grout calculation example
300 mm × 300 mm tiles, 8 mm thick, with 3 mm joints use 0.26 kg/m².
For 3 m × 2 m plus 10% extra, that is 1.69 kg — 1 bag of 5 kg.
Tips before you buy
- Mix only what you can use in the working time printed on the bag.
- Use the same grout batch for the whole job to keep the colour even.
- Epoxy grout has a different density and coverage — use the manufacturer's chart.
Frequently asked questions
How much grout do I need per m²?
For 30 × 30 cm tiles with 3 mm joints it's only about 0.25 kg/m². For 5 × 5 cm mosaics it can be 0.5–1 kg/m² or more.
Does tile thickness matter?
Yes — the joint is filled to the full tile thickness, so thicker tiles need proportionally more grout.
Also searched as: tile grout calculatorhow much grout do I needgrout estimator
Sources
- Method: joint volume × density, the relationship used in grout manufacturers' consumption calculators.
- Pack sizes: the usual shop sizes — 1 kg packets in Pakistan and India, 2–20 kg in Europe, 10 lb and 25 lb bags in the US. Pick yours or enter its weight.
Formulas last reviewed: September 30, 2026 ·How we check our formulas