Grout Calculator

Calculate how many pounds of grout you need for a tile installation. Enter your tile dimensions, joint width, tile thickness, and total area to get an accurate estimate — including how many 25-lb bags to buy.

Grout Quantity Calculator

Grout Calculation Formula

The amount of grout needed depends on the tile size, joint width, and tile thickness. The standard industry formula is:

lbs/ft² = ((TW + TH) / (TW × TH)) × JW × T × 12.7

Where TW = tile width (in), TH = tile height (in), JW = joint width (in), T = tile thickness (in), and 12.7 is a density/conversion factor for standard sanded grout.

Joint WidthGrout TypeTypical Use
1/16" – 1/8"Unsanded groutSmall tiles, glass, stone
1/8" – 3/8"Sanded groutMost floor/wall tiles
3/8" – 1/2"Wide-joint sandedLarge pavers, flagstone
Over 1/2"Mortar mixExterior, heavy stone

Frequently Asked Questions

Should I use sanded or unsanded grout?+
Use unsanded grout for joints narrower than 1/8 inch — it's smoother and won't scratch delicate tile surfaces like polished marble or glass. Use sanded grout for joints 1/8 inch and wider — the sand adds strength and reduces shrinkage in wider gaps. For most standard tile installations, sanded grout is the right choice.
How much extra grout should I buy?+
Always buy at least 10% extra to account for waste, mixing losses, and touch-ups. For irregular or hand-made tiles, add 15–20% because the edges are less uniform. It's also smart to keep a partial bag sealed for future repairs — grout color can vary between batches, so having extra from the same lot is invaluable if a tile cracks later.

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