Grout Calculator
Pounds of grout for any tile size, joint width and area.
Enter your values
Enter the tile length in in.
Enter the tile width in in.
Enter the tile thickness in in.
Enter the joint width in in.
Enter the area to tile in sq ft.
Enter the bag size in lb.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Grout needed
- 11.72 lb
- Bags to buy
- 2 x 10 lb
- Coverage rate
- 0.098 lb per sq ft
- With 10% waste
- 12.89 lb
Working
- 1((12+12)/(12x12)) x 0.125 x 0.375 x 12.5 = 0.098 lb/ft2
Quick answer
Grout volume depends on tile size, joint width and depth. Smaller tiles and wider joints need far more grout per square foot.
lb/ft2 = (L+W)/(L x W) x joint x thickness x 12.5
At a glance
| What it does | Pounds of grout for any tile size, joint width and area. |
|---|---|
| Category | Home & DIY |
| Inputs needed | Tile length, Tile width, Tile thickness, Joint width, Area to tile, Bag size |
| Main output | Grout needed |
| Formula | lb/ft2 = (L+W)/(L x W) x joint x thickness x 12.5 |
| Cost | Free — no sign-up, no download |
How to use the Grout Calculator
- 1Enter the real tile dimensions and thickness from the box.
- 2Set the joint width you plan to use with your spacers.
- 3Buy 10% extra so you can mix a consistent colour throughout.
Inputs explained
- Tile length(in)
- Enter the tile length in in.
- Tile width(in)
- Enter the tile width in in.
- Tile thickness(in)
- Enter the tile thickness in in.
- Joint width(in)
- Enter the joint width in in.
- Area to tile(sq ft)
- Enter the area to tile in sq ft.
- Bag size(lb)
- Enter the bag size in lb.
Worked example
Using the values the calculator loads with:
Inputs
- Tile length12 in
- Tile width12 in
- Tile thickness0.375 in
- Joint width0.125 in
- Area to tile120 sq ft
- Bag size10 lb
Results
- Grout needed11.72 lb
- Bags to buy2 x 10 lb
- Coverage rate0.098 lb per sq ft
- With 10% waste12.89 lb
- ((12+12)/(12x12)) x 0.125 x 0.375 x 12.5 = 0.098 lb/ft2
Frequently asked questions
Sanded or unsanded grout?
Sanded for joints 1/8 inch and wider; unsanded for narrower joints and polished stone that sand would scratch.
Why does mosaic tile use so much grout?
Grout volume scales with the total joint length per square foot. Small tiles have far more joint per area, sometimes five times as much as large format.
What do I need to enter into the Grout Calculator?
Just 6 values: tile length, tile width, tile thickness, joint width, area to tile, bag size. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Grout Calculator work out the answer?
Grout volume depends on tile size, joint width and depth. Smaller tiles and wider joints need far more grout per square foot. It applies the formula lb/ft2 = (L+W)/(L x W) x joint x thickness x 12.5 and shows the working so you can check each step by hand.
Is the Grout Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.