Free grout calculator: estimate how much tile grout you need by weight and volume. Input tile size, joint width, and density. Avoid buying too much or running out mid-project.
Grout is the unsung hero of tiling — it seals joints against water, absorbs movement, and defines the final look. But estimating grout quantity is surprisingly complex: it depends on tile size, joint width and depth, and the type of grout you're using. This calculator handles the geometry so you buy the right amount.
Enter your total tiled area, tile dimensions, and your planned joint width and depth. The density field defaults to cementitious grout (1.6 kg/L) — switch to 2.3 if you're using epoxy. The waste slider starts at 15% because grout mixing often leaves residue in the bucket and on tools. The result shows weight in kilograms and volume in liters.
Cementitious grout has a typical density of 1.6 kg/L and is used for joints 3–12 mm wide. Epoxy grout has a density around 2.3 kg/L, is more chemical-resistant, and is recommended for joints 1–3 mm. Check the packaging: the density is often printed in the technical data sheet as 'specific gravity' or 'wet density.'
Smaller tiles create more joints per square meter, so they use more grout. Mosaic tiles (2×2 cm) can use 5–10 times more grout than large-format tiles (60×60 cm). When in doubt, buy a little extra — matching grout color from a different batch is difficult and dried grout can be stored for the next project.
The joint width should match the tile size: 2–3 mm for rectified tiles (< 30 cm), 4–6 mm for standard tiles (30–60 cm), and 6–12 mm for large-format or handmade tiles with irregular edges. The depth should equal the tile thickness. Wider joints need significantly more grout — doubling the joint width roughly doubles the grout quantity.