Grout Calculator – How Much Grout Do I Need? | CalcLoft
Find out exactly how many pounds of grout you need for any tile size and joint width.
How to estimate grout
Grout fills the joints between tiles. The amount depends on four things: tile size, tile thickness, joint width, and total area. Smaller tiles mean more joints (and more grout); wider gaps and thicker tiles also use more. Our calculator applies the standard formula and adds 10% for waste.
Sanded vs. unsanded grout
| Type | Best for | Gap |
|---|---|---|
| Unsanded | Delicate tiles, walls, polished stone | Under 1/8 in |
| Sanded | Floors, most standard tiles | 1/8 in and wider |
Quick reference
As a rough guide, a 25 lb bag of sanded grout covers about 100-150 sq ft with 12×12 tiles and 1/4-inch joints. Use the calculator above for your exact tile setup.
Grout calculator FAQ
How much grout for 100 sq ft of 12x12 tile?
With 12×12 tiles, 3/8-inch thickness and 1/4-inch joints, you need about 9 lb — one 25 lb bag is more than enough (or share with a second project).
Why do small tiles need more grout?
Small tiles have more joints per square foot. A mosaic floor can use 3-4× more grout than a large-format floor.
Should I buy extra grout?
Yes — color matching across batches is unreliable. Buy one extra bag and store it for repairs.
Not sure which calculator you need?
Browse all free home improvement calculators in one place.