How much grout do you need?
Enter the room, tile size, tile thickness and joint width. You get pounds of grout and bags to buy, with 10% added for waste.
How the grout calculator works
Every tile owns one long joint and one short joint. The joint volume per tile is (length + width) × joint width × joint depth, where the depth is the tile’s thickness. We scale that to your area, convert it to grout powder at about 1.8 kg per litre of joint, and add 10% for waste. This is the same formula tile-setting brands publish; brands differ a little, so the bag’s own chart wins.
Grout per 100 sq ft, by tile size
3/8″ (10 mm) thick tile, 10% waste included.
| Tile size | 1/16″ joint | 1/8″ joint |
|---|---|---|
| 12" × 12" | 4.0 lb | 8.0 lb |
| 12" × 24" | 3.0 lb | 6.0 lb |
| 24" × 24" | 2.0 lb | 4.0 lb |
| 24" × 48" | 1.5 lb | 3.0 lb |
| 6" × 24" plank | 5.0 lb | 10.1 lb |
Grouting tips
- Pull every leveling clip top and clean the joints before you grout. How to remove clips.
- Mix only what you can use in about 30 minutes, and keep the water ratio the same batch to batch so the colour stays even.
- Buy all the grout for one floor from the same lot number.
- The joint width is set by your clips or spacers. Which clip size?
Frequently asked questions
How much grout do I need per square foot?
It depends on the tile size, tile thickness and joint width. For 12×24 tile, 3/8" thick, with a 1/8" joint, plan on roughly 6 lb per 100 sq ft including 10% for waste. Smaller tile and wider joints need more.
How do you calculate grout?
Each tile owns one long and one short joint. Multiply (tile length + tile width) by the joint width and the joint depth (the tile thickness) to get the joint volume per tile, scale it to your area, then convert volume to pounds of grout powder and add about 10% for waste.
Sanded or unsanded grout?
Joints of 1/8" and wider usually take sanded grout. Narrower joints, like the 1/16" common with rectified porcelain, usually take unsanded grout. Follow the grout maker's joint range.
How many square feet does a 25 lb bag of grout cover?
Anywhere from under 100 to several hundred square feet: small tile with wide joints uses far more than large tile with tight joints. Enter your tile and joint above, or check the coverage chart printed on the bag.
Setting the tile first?
The clip calculator counts leveling clips and wedges for the same room, and adds them to your order.