Tile grout calculator: how much grout do I need?
1 bag of 10 lb
7.05 lb of MAPEI Ultracolor Plus FA with 10% waste · 156 sq ft per 10 lb on its data sheet for 12 × 12 × 3/8 in tile at a 1/8 in joint · for 10 × 10 ft
Run your own numbers
Enter it the way you measured it: 4.5, 4 1/2,
3/8 or 10' 6".
1 bag of 10 lb
7.05 lb of MAPEI Ultracolor Plus FA with 10% waste · 156 sq ft per 10 lb on its data sheet for 12 × 12 × 3/8 in tile at a 1/8 in joint
Source: Grout coverage charts on the data sheets of MAPEI, LATICRETE, CUSTOM, TEC and Bostik, read October 26, 2026. Read the source
Grouting 100 sq ft of 12 × 12 × 3/8 in tile with 1/8 in joints takes 7.05 lb of MAPEI Ultracolor Plus FA with 10% waste, from the 156 sq ft per 10 lb on its data sheet: one 10 lb bag.
A worked example
A 14 by 9 1/2 ft floor of 6 × 24 in plank tile, 3/8 in thick, with 3/16 in joints and CUSTOM Prism needs 13.2 lb, one 17 lb box. The floor is 133 sq ft. Prism's chart gives 189 sq ft per 17 lb box for 6 × 24 × 3/8 in tile at a 3/16 in joint, so 11.96 lb, and 13.2 lb with 10% waste: one box covers it with about 3.8 lb to spare.
How much grout per square foot of tile?
For 12 × 12 × 3/8 in tile at a 1/8 in joint the charts give 0.049 lb per sq ft for CUSTOM Prism (348 sq ft per 17 lb box), 0.064 for MAPEI Ultracolor Plus FA (156 per 10 lb), 0.069 for TEC Power Grout 550 and 0.071 for Bostik TruColor. Prism is a lightweight grout: 17 lb covers what a 25 lb bag does.
Why does small tile take so much more grout?
More joint per square foot. On MAPEI's chart 10 lb of Ultracolor Plus FA covers 156 sq ft of 12 × 12 in tile at a 1/8 in joint but 39 sq ft of 2 × 2 in mosaic: four times the grout for the same floor.
What else it is called
Also searched as a tile grout calculator, grout coverage calculator or grout calculator in square feet, and by brand: MAPEI, LATICRETE, CUSTOM, TEC or Bostik grout calculator. Thinset, the mortar under the tile, is a different product and a different calculation.
Grout per 100 sq ft by brand
| Tile, in | MAPEI Ultracolor Plus FA, lb | MAPEI Kerapoxy CQ, gal | LATICRETE PermaColor Grout, lb | CUSTOM Prism, lb | TEC Power Grout 550, lb | Bostik TruColor, lb |
|---|---|---|---|---|---|---|
| 2 × 2 × 1/4 | 25.6 | 1.79 | 24.8* | 17.7 | 27.5 | 28.1 |
| 4 1/4 × 4 1/4 × 1/4 | 12 | 0.88 | 11.7* | 8.85 | 12.9 | 13.4* |
| 6 × 6 × 1/4 | 8.55 | 0.63 | 8.27* | 6.39 | 9.15 | 9.53* |
| 6 × 24 × 3/8 | 8 | 0.6* | 7.75* | 6.09 | 8.58 | 8.93* |
| 12 × 12 × 3/8 | 6.41 | 0.48* | 6.2* | 4.89 | 6.86 | 7.14 |
| 12 × 24 × 3/8 | 4.83 | 0.36* | 4.66 | 3.69 | 5.15 | 5.36* |
| 18 × 18 × 3/8 | 4.29 | 0.32* | 4.13* | 3.28 | 4.57 | 4.76 |
| 24 × 24 × 3/8 | 3.22 | 0.24* | 3.11 | 2.35* | 3.43 | 3.56 |
Grout for 100 sq ft at a 1/8 in joint, before waste. Plain figures come straight from each data sheet; the ones with * are tile sizes the sheet does not list, worked from the joint volume with our fit to that chart. Kerapoxy CQ is in U.S. gallons.
Where the numbers come from
- MAPEI Ultracolor Plus FA Technical Data Sheet (September 10, 2026): coverage per 10 lb for 16 tile sizes and joints from 1/16 to 3/4 in, e.g. 156 sq ft for 12 × 12 × 3/8 in tile at 1/8 in; bags of 10 and 25 lb. Read October 26, 2026. MAPEI Ultracolor Plus FA data sheet (PDF)
- MAPEI Kerapoxy CQ Technical Data Sheet (May 4, 2026): coverage per U.S. gallon for 15 tile sizes and joints from 1/16 to 3/8 in, e.g. 159 sq ft for 6 × 6 × 1/4 in tile at 1/8 in; kits of 1 and 2 gal. Kerapoxy CQ data sheet (PDF)
- LATICRETE Data Sheet DS-254.3-1123: PermaColor Grout coverage per 25 lb bag, e.g. 804 sq ft for 24 × 24 × 3/8 in tile at 1/8 in, and «Add 10% for waste, spillage and clean-up, and another 10% - 15% when grouting unglazed quarry tile». LATICRETE grout card (PDF)
- Custom Building Products Prism sell sheet SS160 9/25R: coverage per 17 lb box, e.g. 348 sq ft for 12 × 12 × 3/8 in tile at 1/8 in; «17 lbs. covers the same area as a typical 25 lb. bag». Prism sell sheet (PDF)
- TEC Power Grout 550 Product Data Sheet DS550_R0826-20: coverage per pound, e.g. 14.58 sq ft for 12 × 12 × 3/8 in tile at 1/8 in; bags of 7, 10 and 25 lb. Power Grout data sheet (PDF)
- Bostik TruColor Technical Data Sheet (August 8, 2025): coverage per 9 lb and 18 lb unit, e.g. 126 sq ft per 9 lb for 12 × 12 × 3/8 in tile at 1/8 in. Its 3 × 6 and 4 × 4 in rows give twice what the joint volume allows in both charts, so they are not used. TruColor data sheet (PDF)
- No brand prints a formula, only charts. When your tile and joint are on the chart, the chart figure is used as printed. When they are not, the joint volume (144 × (length + width) ÷ (length × width) × joint × thickness cubic inches per sq ft) is multiplied by a density fitted to that brand's chart, the median of its cells: 0.057 lb per cu in for Ultracolor Plus FA, 0.0551 PermaColor, 0.0417 Prism, 0.061 Power Grout, 0.0635 TruColor; Kerapoxy's chart matches the exact joint volume in gallons. That fit is ours, not the manufacturer's.
The charts assume joints filled to the full tile thickness. Tiles with a pillowed or rounded edge, and stone set lower than its thickness, take less; unglazed quarry tile takes 10 to 15% more by LATICRETE's guideline.
By Javier Miralles · Last updated . How this site is made.
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