Grout Calculator
Enter your tile size, grout joint width, and area to estimate the pounds of grout needed to fill the joints, with waste included.
Results
- Grout needed
- 26 lb
- 25 lb bags
- 2 bags
- Per sq ft
- 0.24 lb
Estimates only. Round up and buy a little extra to account for waste, spills, and breakage.
Grout usage depends on four things: tile size, tile thickness, joint width and joint depth. This calculator combines them into pounds of grout and a bag count.
Small mosaic tiles use several times more grout per square foot than large format tile, which is why generic coverage numbers on the bag are often wrong for your job.
Also works as a tile grout calculator, grout coverage estimator, and thinset quantity calculator.
How to use the grout calculator
- Enter the tiled area in sq ft.
- Enter the tile length in in.
- Enter the tile width in in.
- Enter the tile thickness in in.
- Enter the grout joint width in in.
- Enter the waste factor in %.
- Optionally add a price to estimate the total project cost.
- Read your quantities instantly — no sign-up, and you can print the estimate to take to the supplier.
Worked example
Inputs
- Tiled area
- 100 sq ft
- Tile length
- 12 in
- Tile width
- 12 in
- Tile thickness
- 0.375 in
- Grout joint width
- 0.125 in
- Waste factor
- 10 %
Results
- Grout needed
- 26 lb
- 25 lb bags
- 2 bags
- Per sq ft
- 0.24 lb
Using the example values above, the grout calculator returns 26 lb (grout needed). Change any field to match your own project and the numbers update instantly.
Joint width guidance
Rectified large format tile can go as tight as 1/16 to 1/8 inch. Standard ceramic wall tile typically uses 1/8 inch, floor tile 3/16 inch, and natural stone or handmade tile 1/4 inch or more.
Use sanded grout for joints 1/8 inch and wider, unsanded for narrower joints and polished stone that sand would scratch.
Mixing and waste
Mix only what you can install in about 30 minutes. Grout that starts to set cannot be re tempered with more water without losing color consistency and strength.
Order 10 percent extra and buy all bags from the same dye lot so the color matches across the whole floor.
How much extra should I order?
Always order a little extra. A 5% waste factor suits simple, square projects; 10% is right for most jobs; bump it to 15–20% for irregular shapes, diagonal patterns, or uneven ground. Running short almost always costs more than the leftover material.
Formula
Grout per sq ft depends on tile size, joint width, and tile thickness; multiply by area and add waste.
Frequently asked questions
- How much grout do I need for tile?
- Grout use depends on tile size, joint width, and thickness — smaller tiles and wider joints need much more grout per square foot.
- Does tile size change grout amount?
- Yes. Large tiles have less joint length per square foot, so they use far less grout than small mosaic tiles.
- How much grout do I need per square foot?
- Roughly 0.1 to 0.2 lbs per sq ft for 12 by 12 tile with 1/8 inch joints, and up to 1 lb per sq ft for mosaics.
- How much does a bag of grout cover?
- A 25 lb bag covers about 100 to 150 sq ft of 12 inch tile with 1/8 inch joints, and far less with small tile or wide joints.
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