How much grout do I need for 100 sq ft of 12x12 tile?

For 12x12 tile with 1/8-inch joints: approximately 8-12 lbs of grout per 100 sq ft. A 10-lb bag typically covers 80-120 sq ft. For larger tile (24x24), less grout is needed due to fewer joints.

What is the difference between sanded and unsanded grout?

Sanded grout: for joints 1/8-inch and wider, contains fine sand for strength and crack resistance. Unsanded grout: for joints under 1/8-inch, used with glass and polished stone tiles to avoid scratching.

How long does grout take to cure?

Grout dries to the touch in 1-2 hours but takes 72 hours (sanded) to 7 days (epoxy) to fully cure. During curing, keep the area ventilated and avoid wet mopping.

Should I seal my grout?

Yes - grout is porous and absorbs water and stains. Seal sanded grout in showers, kitchen backsplashes, and entryways every 1-2 years. Epoxy grout does not require sealing.

Grout Calculator

Estimate pounds of grout needed based on tile size and joint width.

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Grout Calculator

Tile Area(sq ft)

Tile Size

Grout Joint Width

For a typical 50 sq ft kitchen backsplash using 3x6 subway tile with 1/8-inch joints, you will need roughly 4-6 lbs of sanded grout — one 10-lb bag covers the project with plenty left over for touch-ups. Epoxy grout costs 2-3 times more than sanded but never needs sealing and resists stains better in kitchens and bathrooms.

What This Calculator Does

The Grout Calculator estimates the pounds of sanded or unsanded grout needed for a tile installation based on tile area, tile size, and grout joint width. Enter your project details to get the total pounds of grout and the number of bags required.

Grout fills the joints between tiles, providing structural integrity and a finished appearance. The amount needed depends on the tile size (larger tiles need less grout), tile thickness, and joint width. Standard residential tile installations use 1/8-inch grout lines with 12x12 tiles.

Unsanded grout is used for joints under 1/8 inch (glass and polished stone tiles). Sanded grout is used for joints 1/8 inch and wider - the sand prevents cracking and provides additional strength.

How to Use

Measure the total tile area in square feet.
Select your tile size and grout joint width from the dropdowns.
Enter the area and select your options in the calculator above.
Click "Calculate" to get the pounds of grout and bags needed.
Grout is sold by weight (10-lb and 25-lb bags) - buy slightly more than calculated for mixing consistency.

Worked Examples

Kitchen Backsplash Grout Estimate

A 12 x 3.5 ft kitchen backsplash (42 sq ft) using 3x6 inch subway tile with 1/8-inch sanded grout joints.

→Total tile area: 12 ft x 3.5 ft = 42 sq ft.
→For 3x6 subway tile with 1/8-inch joints: approximately 6-7 lbs of grout per 50 sq ft.
→42 sq ft needs roughly 5-6 lbs of sanded grout — one 10-lb bag is sufficient.
→At $15-$20 per 10-lb bag of sanded grout: approximately $15-$20 for material.

Result: A 42 sq ft kitchen backsplash requires approximately 5-6 lbs of sanded grout, or one 10-lb bag at $15-$20.

Mix grout in small batches — mixed grout has a working time of about 30 minutes before it starts to stiffen. For small backsplash projects, half a bag at a time prevents waste.

Reference Table

Grout estimator - pounds by tile size and joint width per 100 sq ft
Tile Size	1/8-in Joint	1/4-in Joint	Per 100 sq ft	10-lb Bags
4x4 in	25 lbs	35 lbs	25-35 lbs	3 bags
6x6 in	15 lbs	22 lbs	15-22 lbs	2 bags
12x12 in	8 lbs	14 lbs	8-14 lbs	1 bag
18x18 in	5 lbs	9 lbs	5-9 lbs	1 bag
24x24 in	3 lbs	6 lbs	3-6 lbs	1 bag