Flooring & tileFree calculator
Work out how much grout to buy for a tiling job. Enter the area, tile size, joint width and tile thickness to see the weight of grout and the number of bags.
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How to measure
- Measure the length and width of the tiled area.
- Measure one tile, and the thickness of the tile.
- Decide the joint width: 1/16–1/8 in (1.5–3 mm) for wall tiles, 1/8–1/4 in (3–6 mm) for floor tiles.
The formula
Grout (kg per m²) = ((tile length + tile width) ÷ (tile length × tile width))
× joint width × tile thickness × 1.6
(all sizes in millimetres; 1.6 = grout density)Worked example
An 8 × 10 ft floor with 12 × 12 in tiles, 1/8 in joints and 3/8 in thick tiles needs about 5.7 lb of grout including 10% extra, so one 25 lb bag is plenty.
Tips before you buy
- Smaller tiles have more joints and need much more grout per square foot.
- Mix only what you can use in about 30 minutes.
- Use epoxy grout in showers and kitchens for better stain resistance.
Frequently asked questions
Sanded or unsanded grout?
Use unsanded grout for joints narrower than 1/8 in (3 mm) and sanded grout for wider joints.
How long does grout take to dry?
Most cement grouts can take light foot traffic after 24 hours and fully cure in about 3 days. Check the bag.
Should I seal grout?
Sealing cement grout helps resist stains and moisture. Epoxy grout does not need sealing.
Results are estimates for planning only. Always check quantities with your supplier before you buy.