Grout Calculator: How Much Grout for Tile
This grout calculator tells you how much grout to buy for a floor, shower wall, backsplash or countertop. Enter the area you are tiling, the tile length and width, the tile thickness and the width of the grout joint. The tool works out the volume of the joints, converts it to pounds or kilograms of dry grout, adds a waste allowance and counts how many bags you need. Small tiles and wide joints need much more grout than large tiles with thin joints, which is why a generic rule of thumb often fails. Choose imperial or metric units, pick the bag size and get a number you can take to the store.
Grout Calculator
Work out how much grout to buy for a floor, wall or backsplash from the tile size, joint width and thickness. Pounds, kilograms and bags.
How to use the Grout Calculator
- Choose imperial or metric units.
- Enter the area to tile, the tile length and width and the tile thickness.
- Enter the grout joint width and the extra waste percentage.
- Pick your bag size and read the pounds and bags needed.
Features
- Imperial and metric units
- Uses tile size, thickness and joint width
- Waste allowance
- Pounds, kilograms and bag count
- Joint volume and coverage per bag
- Works for floors, walls and backsplashes
Frequently asked questions
How much grout do I need per square foot?
It depends on the tile size and joint width. 12 inch tiles with 1/8 inch joints and 3/8 inch thickness need roughly 0.08 pounds per square foot, while small mosaics can need ten times more.
What is the grout joint width?
It is the gap between tiles. Floor tile often uses 1/8 to 3/8 inch joints and wall tile 1/16 to 1/8 inch. Rectified tile can use very thin joints.
How do I calculate grout by hand?
Joint volume per tile area is (length + width) × joint width × thickness divided by (length × width). Multiply by the area, convert to weight and add waste.
Should I add extra for waste?
Yes. Adding 10 to 15 percent covers spills, uneven tiles and mixing leftovers. The default here is 10 percent.
Sanded or unsanded grout?
Use sanded grout for joints wider than 1/8 inch and unsanded for narrow joints or soft stone that scratches. The amount needed is about the same.