Grout Calculator — Bags Needed for Tiling
Enter your tile dimensions, joint width, grout depth and total area to estimate the weight of grout needed in kilograms and the number of standard bags to buy. A configurable waste allowance covers mixing losses and spillage.
mm
mm
mm
mm
m²
kg/L
%
Including waste allowance
2%
jointsTile area
98%
Grout joints
2%
- 1
Joint volume per m²
3 × 8 × (300 + 300) ÷ (300 × 300) = 0.16 L/m² - 2
Grout weight per m²
0.16 L/m² × 1.75 kg/L = 0.28 kg/m² - 3
Net grout needed
0.28 kg/m² × 10 m² = 2.8 kg - 4
Total with waste allowance
2.8 × 1.1 = 3.1Waste factor covers mixing losses, spillage and excess cuts.
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Grout volume per m² = J × D × (W + H) / (W × H) litres, where J is joint width, D is tile thickness, W and H are tile dimensions (all in mm). Multiply by grout density (~1.75 kg/L) and total area, then add a 10–15% waste allowance to get total kilograms. Divide by bag size and round up to find bag count.
Formula
How this is calculated
Grout fills the gaps (joints) between tiles. The volume of joints per square metre of tiled surface depends on the joint width, the grout depth (equal to the tile thickness), and the tile dimensions. For a tile of width W and height H (both in mm) with a joint of width J (mm) and depth D (mm), the joint volume per m² is approximately J × D × (W + H) / (W × H) litres — derived from the fraction of the total surface area occupied by horizontal and vertical joints.
This formula is an approximation valid when the joint width is small compared to the tile size. It slightly underestimates for very narrow tiles or very wide joints, but is accurate to within a few percent for typical tile sizes (100 mm and above) and standard joints (2–10 mm). Multiplying by the grout's mixed density (kg per litre) gives the weight per square metre; multiplying by the total area and the waste factor gives the total weight to purchase.
A 10–15% waste allowance is standard: grout is mixed in batches and some is lost to spillage, the mixing container and surface texture. For complex tile layouts, patterned cuts or manual mixing, increase the allowance to 15–20%. Divide the total weight by the bag size (5 kg or 25 kg) and round up to get the bag count.
Mistoqsijiet frekwenti
Smaller tiles have more joints per square metre, so the total joint area is much higher. A mosaic tile (50×50 mm) with a 3 mm joint uses roughly 6× more grout per m² than a 300×300 mm tile with the same joint width, because the ratio of joint area to tile area scales as (W+H)/(W×H), which grows as tiles get smaller.
Use the tile thickness — grout fills the joint from the tile face back to the adhesive layer. Wall tiles are typically 6–8 mm thick; floor tiles 8–12 mm. If you are regrouting without removing tiles, use the joint depth you are actually filling rather than the full tile thickness.
The formula is the same for both. The difference is density: unsanded grout (used for joints under 3 mm) mixes to about 1.6–1.8 kg/L; sanded grout (for joints 3 mm and wider) to about 1.7–1.9 kg/L. Adjust the density field for your specific product's datasheet.
Magħruf ukoll bħala
TG we-Calculate Editorial Team. (2026). Grout Calculator — Bags Needed for Tiling [Online calculator]. TG we-Calculate. https://we-calculate.com/mt/calculator/grout-calculator
TG we-Calculate Editorial Team. "Grout Calculator — Bags Needed for Tiling." TG we-Calculate. 2026. https://we-calculate.com/mt/calculator/grout-calculator.
TG we-Calculate Editorial Team, "Grout Calculator — Bags Needed for Tiling," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/mt/calculator/grout-calculator
@misc{wecalculate_grout_calculator, title = {Grout Calculator — Bags Needed for Tiling}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/mt/calculator/grout-calculator}}, year = {2026}, note = {TG we-Calculate} }
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