Grout Calculator
To grout a 10 × 12 ft floor of 12-inch tile with 1/8-inch joints you need about 132 sq ft plus 10% waste — 2 bags, based on roughly 110 sq ft of coverage per 25 lb bag.
Reviewed by The ponderloop teamUpdated 2026-07-11How we calculate
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How this number is calculated
0 sq ft (no waste added) ÷ 110 sq ft per bag = 0 bags
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- Sanded tile grout
- Grout float
- Grout sponge
- Grout sealer
- 2-gallon bucket
- Grout haze remover
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Methodology & assumptions
We compute the tiled area as length × width in feet, subtract any untiled openings you enter, then add 10% waste to cover mixing loss and touch-ups. The result is divided by the bag coverage (about 110 sq ft per 25 lb bag, assuming 12x12 in. tile with 1/8 in. joints) and rounded up to the next whole bag.
- Typical US retail price range for sanded tile grout, 2026
- Manufacturer bag coverage specifications (12x12 in. tile, 1/8 in. joints)
Worked examples
| Room | Result |
|---|---|
| 10 × 12 ft floor, 12-inch tile | 120 sq ft + 10% waste ≈ 132 sq ft → 2 bags |
| 15 × 20 ft floor, 12-inch tile | 300 sq ft + 10% waste ≈ 330 sq ft → 3 bags |
| 8 × 10 ft bathroom floor, 12-inch tile | 80 sq ft + 10% waste ≈ 88 sq ft → 1 bag |
Frequently asked questions
- How many bags of grout do I need?
- Multiply the tiled length by width in feet to get the square footage, subtract any untiled openings, then add 10% for waste. Divide by the coverage per bag (about 110 sq ft for a 25 lb bag of sanded grout on 12-inch tile with 1/8-inch joints) and round up to the next whole bag.
- Does tile size or grout joint width change how much grout I need?
- Yes, significantly. The 110 sq ft per bag figure assumes 12-inch tile with narrow 1/8-inch joints — that ratio of grout line to tile face is small. Smaller tile, mosaics, or subway tile have far more linear feet of joint per square foot, and wider joints (3/16 in. or 1/4 in.) hold much more grout per foot. Either factor can cut real coverage to a third of the 12-inch/1/8-inch baseline, so size up a bag or two if your tile is smaller or your joints are wider.
- Should I use sanded or unsanded grout?
- Use sanded grout for joints 1/8 inch or wider (it resists shrinking and cracking); use unsanded grout for hairline joints under 1/8 inch, typically on polished stone or glass tile that scratches easily.
- Should I round up or down when figuring out how many bags to buy?
- Always round up to a full bag. Grout bags are inexpensive relative to the cost of a stalled job, and matching the exact color and lot later can be difficult once a bag is discontinued or reformulated.