Tile Grout Calculator

How much tile grout you need, in pounds, kilograms and bags, from the tiled area, tile size and thickness, and joint width.

Joints are assumed filled to the full tile thickness. 3/8 in (≈10 mm) is typical for floor tile.
1/16 in (1.5 mm) for wall tile, 1/8–1/4 in (3–6 mm) for floors.
About 1.9 kg/L for cement grout, as implied by Sika’s published coverage table. Use your product’s data sheet value if given.
%
Covers mixing loss, porous edges and joints deeper than expected.
Sanded grout is commonly sold in 25 lb bags, unsanded in 10 lb bags.
$per bag
Your rate is remembered on this device.
Grout needed (incl. waste)
8.5
Bags to buy
1 bags
Joint volume (before waste)
1.84
Coverage rate (before waste)
0.377 kg/m²
Estimated grout cost
$20.00
Excludes sealer, sponges and labor.

Estimate generated with SortedSums: https://sortedsums.com/grout-calculator/. For informational purposes only; verify before relying on it.

Estimate only. This tool is for informational and educational purposes. Results depend on your inputs and simplifying assumptions, and are not a substitute for professional engineering, design or financial advice. Always verify with a qualified professional and applicable codes before purchasing, building or making decisions.

How it’s calculated

Grout fills a narrow prism around every tile. Per unit of tiled area, the joint length is (L + W) ÷ (L × W), so the grout volume is that length × joint width × joint depth. Multiply by the grout’s density for weight, then add waste.

Grout volume = area × (L + W) ÷ (L × W) × joint width × tile thickness Grout weight = volume × density × (1 + waste%) Bags = ⌈ weight ÷ bag size ⌉

Check against Sika’s data sheet: 30 × 30 cm tiles, 10 mm thick, 3 mm joints, 1.9 kg/L: (300 + 300) ÷ (300 × 300) × 3 × 10 × 1.9 = 0.38 kg/m², matching the published 380 g/m².

Example: 100 ft² of 12 × 12 in tile, 3/8 in thick, 1/8 in joints. Volume = 14,400 in² × (24 ÷ 144) × 0.125 × 0.375 = 112.5 in³ = 1.84 L. At 1.9 kg/L that is 3.50 kg (7.72 lb); with 10% waste 8.5 lb, so one 25 lb bag.

Frequently asked questions

How much grout do I need per square foot?

It depends on tile size and joint width. 12 × 12 in tile, 3/8 in thick with 1/8 in joints, uses about 0.08 lb per square foot; small mosaics with the same joints use several times more.

Sanded or unsanded grout?

Manufacturers generally recommend unsanded grout for joints of 1/8 in (3 mm) or less and sanded grout for wider joints. Follow the grout bag’s joint-width range.

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Sources

Formulas are taken from the free public references above. Results are provided “as is” for informational and educational purposes only. See our disclaimer.

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