How Much Grout Do I Need?

Enter your tile size, joint width, and total area to find out exactly how many bags of grout to buy — with waste included.

How to Calculate Grout Needed

The amount of grout depends on tile size, joint width, tile thickness, and grout type density. The industry-standard formula from the TCNA Handbook calculates total joint volume, converts it to pounds using grout-specific density, adds a 10% waste buffer, then divides by your bag size for an exact count.

Key insight: Joint width has far more impact than tile size. A ¼" joint uses roughly twice as much grout as a ⅛" joint on the same tile. Always buy at least 10% extra — grout is sold in production batches, and color can vary between batches.

Sanded vs. Unsanded vs. Epoxy Grout

Type	Best For	Joint Width	Sealing Required?
Sanded	Floors, large-format tiles, natural stone	⅛" and wider	Yes — annually
Unsanded	Wall tiles, polished stone, glass, small joints	Under ⅛"	Yes — annually
Epoxy	Showers, kitchens, pools, commercial	Any width	No — stain-proof

Never use sanded grout on polished marble or glass tile — the sand particles will permanently scratch the surface. Use unsanded or epoxy for those applications.

Grout Quick Reference by Tile Size

Tile Size	Joint Width	~Lbs per 100 sq ft	10 lb bags needed
4×4"	⅛"	~18 lbs	2 bags
6×6"	3/16"	~14 lbs	2 bags
12×12"	¼"	~11 lbs	2 bags
12×24"	¼"	~9 lbs	1 bag
18×18"	⅜"	~10 lbs	1 bag
24×24"	¼"	~7 lbs	1 bag
2×2" mosaic	⅛"	~35 lbs	4 bags

All figures per 100 sq ft, including 10% waste. Actual usage varies by tile porosity, joint depth, and application technique. Always confirm with the product data sheet for your specific grout brand.

Grout Cost by Type (2026)

Grout Type	10 lb bag	25 lb bag	Notes
Sanded cement	$10–$18	$22–$35	Most affordable, seal annually
Unsanded cement	$12–$20	$25–$38	For narrow joints and wall tile
Epoxy (2-part)	$30–$50	$60–$90	No sealing, stain-proof, harder to apply