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Kerapoxy CQ Grout Calculator: How Many Kits Do You Need?
Enter your area, tile size and joint width to see how many gallons of Kerapoxy CQ to buy and which mix of 1 gallon and 2 gallon kits covers it. The calculator uses a joint-volume formula calibrated against the per-gallon coverage chart in MAPEI's US technical data sheet MK 3000150 (edition date April 29, 2026) and never claims more coverage than the chart. For 12 x 12 x 1/2 in tile with 1/8 in joints, MAPEI gives 156 sq ft per gallon; the calculator gives about 152.
MAPEI Kerapoxy CQ coverage
| Tile | 1/16 in | 1/8 in | 1/4 in | 3/8 in |
|---|---|---|---|---|
| 1 x 1 x 1/4 in | 56 | 31 | 18 | 14 |
| 2 x 2 x 1/4 in | 108 | 56 | 31 | 22 |
| 3 x 3 x 1/4 in | 159 | 82 | 43 | 31 |
| 4 x 4 x 3/8 in | 140 | 72 | 37 | 26 |
| 4 x 8 x 1/2 in | 139 | 71 | 37 | 25 |
| 4 x 8 x 3/4 in | 93 | 47 | 24 | 17 |
| 4 x 8 x 1 1/8 in | 62 | 32 | 16 | 11 |
| 4 x 8 x 1 3/8 in | 51 | 26 | 13 | 9 |
| 4 1/4 x 4 1/4 x 1/4 in | 223 | 114 | 59 | 41 |
| 6 x 6 x 1/4 in | 313 | 159 | 82 | 56 |
| 6 x 6 x 1/2 in | 156 | 79 | 41 | 28 |
| 8 x 8 x 3/8 in | 277 | 140 | 72 | 49 |
| 10 x 10 x 3/8 in | 345 | 174 | 89 | 60 |
| 12 x 12 x 1/2 in | 310 | 156 | 79 | 54 |
| 16 x 16 x 3/8 in | 551 | 277 | 140 | 94 |
Source: MAPEI Technical Data Sheet: Kerapoxy CQ Premium, Epoxy Grout and Mortar with Color-Coated Quartz (US, English), MK 3000150 (26-1710), edition date April 29, 2026, read 2026-10-19.
How the calculation works
grout per sq ft = 144 × ((L + W) × J + J²) × T ÷ ((L + J) × (W + J))
units = area × (1 + waste ÷ 100) × grout per sq ft ÷ joint volume one unit fills, rounded up
L and W are the tile length and width, T the tile thickness (the joint is assumed to be filled to full tile depth) and J the joint width, all in inches; the result is in cubic inches. The volume one gallon fills is worked back from the manufacturer's coverage chart and set at the lowest value any cell of the chart implies, so for every tile size in the chart this calculator gives the same or less coverage than the data sheet, never more. Tiles not in the chart use the same formula.
Worked example
A 300 sq ft floor of 12 x 12 x 1/2 in tile with 1/8 in joints and 10% extra: 330 sq ft to grout. Each tile plus its share of joint is a 12.125 × 12.125 in square, and the joint part of it holds (12 + 12) × 1/8 + 1/8² = 3.016 sq in, 1/2 in deep. That works out to 1.48 cubic inches of grout per sq ft of floor. One 1 gal (3.79 L) kit fills about 225 cubic inches of joint, so it covers 225 ÷ 1.48 = 152.2 sq ft. 330 ÷ 152.2 = 2.17 units of 1 gal (3.79 L) kit, or 2.17 × 1 gal = 2.17 gallons of mixed grout. In the sizes on sale, buy 1 × 2 gal kit + 1 × 1 gal kit (3 gal).
MAPEI Kerapoxy CQ key specs
| Product type | Tile grout |
|---|---|
| Package | 1 gal (3.79 L) kit |
| Joint width range | 1/16–3/8 in |
| Coverage (TDS, per 1 gal) | 12 x 12 x 1/2" tile 310 sq ft at 1/16", 156 at 1/8", 79 at 1/4", 54 at 3/8"; 16 x 16 x 3/8" tile 277 at 1/8"; 2 x 2 x 1/4" mosaic 56 at 1/8" (full chart below) |
| Kit sizes | 1 US gal (3.79 L) and 2 US gal (7.57 L); Part A and Part B are packed in the exact ratio, so always mix a complete kit |
| Joint width | 1/16" to 3/8" (1.5 to 10 mm); nonsagging in joints up to 3/8" |
| Joint depth | remove adhesive so that 2/3 of the tile depth is open for grout |
| Mixing | pour all of Part B into Part A, slow-speed mixer at about 300 rpm for 1 minute (or margin trowel for small kits); no water or other materials |
| Pot life and cure | pot life 45–60 min; no walking 24 h, no heavy traffic 48 h, protect from debris 72 h, routine cleaning after 3 days, 10–14 days before water immersion or chemicals, full cure 14 days (73°F, 50% RH) |
| Temperature | substrate and tile 60–90°F (16–32°C) while grouting and for 72 h after; cured grout resists up to 212°F (100°C) |
| Cleanup | water-cleanable; clean after each kit, final wash within 15–20 min (1 US oz of clear dish soap per 3 gal of water if needed) |
| Sealing | not required (TDS) |
| Standards | meets or exceeds ANSI A118.3; ISO 13007 R2/RG; typical VOC 8 g/L (SCAQMD Rule 1168) |
| As a mortar | 1/4 x 1/4 x 1/4" square notch 18 sq ft per gal (36 per 2 gal); 5/32 x 5/32" sawtooth 40 sq ft per gal; max 1/4" under the tile |
| Not for | white or translucent marble, areas with excessive heat; extreme industrial and food-plant floors (MAPEI points to Kerapoxy IEG CQ) |
| Colors and shelf life | 40 colors in 5 collections; 2 years unopened at 73°F (23°C); protect from freezing |
What Kerapoxy CQ is
Kerapoxy CQ is MAPEI's premium two-component, 100%-solids epoxy grout. It can also be used as a setting mortar. The "CQ" stands for color-coated quartz: the color comes from a coated aggregate rather than loose pigment, which MAPEI says is why the grout keeps an even color and cleans back to its original shade. It meets or exceeds ANSI A118.3, is classified R2/RG under ISO 13007, contains MAPEI's BioBlock mold and mildew protection, and does not need sealing.
The US data sheet lists the jobs epoxy is usually chosen for: kitchen countertops and vanities where stains are a worry, heavy-traffic floors such as malls, airports and subway stations, and commercial or institutional floors that see chemicals. As a mortar it is rated for gang showers, pools, spas and fountains. It is nonsagging in joints up to 3/8 inch, so it works on walls as well as floors. For the harshest settings, such as dairies, breweries and high-volume food kitchens, MAPEI points you to its industrial Kerapoxy IEG CQ instead.
Kit sizes and why you always mix a whole kit
Kerapoxy CQ comes as a kit with a Part A resin and a Part B hardener, in two sizes:
- 1 gallon kit: 1 US gal (3.79 L) of mixed grout.
- 2 gallon kit: 2 US gal (7.57 L) of mixed grout.
The two parts are packed in the exact ratio needed to cure, and the data sheet tells you to always mix complete units and add nothing else. You cannot open half a kit for a small repair. That is why the calculator works in whole kits and suggests the smallest mix of 1 and 2 gallon kits that covers your area. The 2 gallon kit costs less per gallon, but pot life is only 45 to 60 minutes and you must clean each kit off the tile before opening the next. On a large floor with one installer, two 1 gallon kits mixed one after the other may be easier to handle than one 2 gallon kit.
How the calculator works
Grout only fills the gaps between tiles, so the amount depends on how much joint there is per square foot of floor. The calculator treats each tile plus half the joint on each side as a rectangle (L + J) by (W + J), where L and W are the tile length and width and J is the joint width. The joint part of that rectangle is (L + W) × J + J² square inches. Multiplying by the tile thickness T, because the joint is filled to full depth, and dividing by the rectangle's area gives grout per square inch of floor. Multiply by 144 and you have cubic inches of grout per square foot.
To turn that into gallons, the calculator needs to know how much joint one gallon of Kerapoxy CQ really fills. Working backwards from all 60 cells of MAPEI's chart, the answer comes out between about 225 and 237 cubic inches per gallon. A US gallon is 231 cubic inches, so the chart is very close to "one gallon of grout fills one gallon of joint", with a small allowance for waste. The calculator uses the lowest value, 224.8, so it never claims more coverage than MAPEI prints. For 12 x 12 x 1/2 inch tile with 1/8 inch joints that gives about 152 sq ft per gallon against MAPEI's 156.
Your waste allowance is then added on top. Epoxy is harder to work than cement grout and any residue left on the tile has to be washed off, so 10 percent is a sensible starting point. Use more for textured or slip-resistant tile: the data sheet warns that coverage on abrasive tile can drop sharply.
Worked example
Say you are grouting a 300 sq ft floor of 12 x 12 inch porcelain, 1/2 inch thick, with 1/8 inch joints, and you allow 10 percent waste.
- Joint area per tile: (12 + 12) × 0.125 + 0.125² = 3.016 sq in.
- Joint volume per tile: 3.016 × 0.5 = 1.508 cu in.
- Rectangle per tile: 12.125 × 12.125 = 147.0 sq in, so grout per sq ft of floor is 1.508 ÷ 147.0 × 144 = 1.477 cu in.
- Coverage per gallon: 224.8 ÷ 1.477 ≈ 152 sq ft.
- Area with waste: 300 × 1.10 = 330 sq ft, so you need 330 ÷ 152 ≈ 2.17 gallons.
- Kits: one 2 gallon kit is not quite enough, so the calculator suggests one 2 gallon kit plus one 1 gallon kit.
Change the joint to 1/16 inch and the same floor needs only about 1.1 gallons; change it to 3/8 inch and it needs about 6.3. Joint width matters more than anything else, so measure your spacers before you buy.
Reading MAPEI's coverage chart
The full chart from the data sheet is reproduced below the calculator. A few patterns are worth knowing:
- Tile thickness matters. The chart has four 4 x 8 inch rows from 1/2 to 1 3/8 inch thick. At 1/8 inch joints coverage falls from 71 to 26 sq ft per gallon as the brick gets thicker, because the joint is deeper.
- Mosaics eat grout. A 1 x 1 inch mosaic at 1/8 inch covers 31 sq ft per gallon, about a fifth of what 12 x 12 tile covers.
- Your tile may be thinner than the chart's. MAPEI lists 12 x 12 tile at 1/2 inch thick. Most 12 x 12 porcelain sold today is about 3/8 inch, which needs about a quarter less grout. Enter your real thickness and the calculator adjusts.
- Sizes not in the chart. Large-format plank and 24 inch tile are not listed. The formula covers them the same way, using the same per-gallon volume.
Before you grout
The data sheet asks for tile and substrate between 60°F and 90°F while grouting and for 72 hours after. Make sure the setting mortar is fully dry, pull all spacers, and clear adhesive from the joints so at least two thirds of the tile depth is open. A grout release can help on porous or textured porcelain and stone; test on a spare tile first, especially with light-colored marble, which epoxy can stain.
Work in small areas. Force the grout into the joints with a hard rubber float, strip the excess at 90 degrees diagonally to the joints, then scrub with cold water and a white nylon pad and lift the residue with a sponge or a terry towel. MAPEI asks for a final wash within 15 to 20 minutes and a check the next day for any tacky haze. Keep foot traffic off for 24 hours, heavy traffic off for 48 hours, and wait 10 to 14 days before filling a shower pan or pool.
Where the numbers come from
Coverage, kit sizes, joint limits and cure times on this page come from MAPEI's US English technical data sheet for Kerapoxy CQ, MK 3000150, edition date April 29, 2026, linked from MAPEI's US product page. We read it on October 19, 2026. MAPEI updates its sheets from time to time, so check the current version before a large order. This calculator is an independent estimate and is not made or endorsed by MAPEI.
FAQ
How much does a gallon of Kerapoxy CQ cover?
It depends on tile size, tile thickness and joint width. MAPEI's US data sheet gives 156 sq ft per 1 gallon kit for 12 x 12 x 1/2 inch tile with 1/8 inch joints, 310 sq ft at 1/16 inch and 54 sq ft at 3/8 inch. Thinner and bigger tile goes further: 16 x 16 x 3/8 inch tile covers 277 sq ft at 1/8 inch. Mosaics use much more: a 1 x 1 inch mosaic at 1/8 inch covers 31 sq ft per gallon. A 2 gallon kit covers twice as much. MAPEI calls these figures approximate.
Can I mix half a kit of Kerapoxy CQ?
No. Part A and Part B are packaged in the exact ratio needed to cure, and the data sheet says to always mix complete units and not add anything else. That is why the calculator rounds up to whole kits. Because pot life is only 45 to 60 minutes and each kit must be cleaned off the tile before you open the next, a few 1 gallon kits are often easier to handle than one 2 gallon kit on a small crew.
Can Kerapoxy CQ be used for 1/2 inch joints?
No. The data sheet limits it to joints from 1/16 to 3/8 inch, and the coverage chart stops at 3/8 inch, so the calculator does too. For wider joints MAPEI's cement-based Ultracolor Plus FA goes to 3/4 inch.
How is Kerapoxy CQ different from Flexcolor CQ?
Both use MAPEI's color-coated quartz, but Flexcolor CQ is a ready-to-use pre-mixed grout (ANSI A118.19) that you open and spread, while Kerapoxy CQ is a two-part 100%-solids epoxy (ANSI A118.3) that you mix and must use within about an hour. Kerapoxy CQ is the one for countertops, heavy commercial traffic, chemical exposure and areas that stay wet; Flexcolor CQ is not for pools or other submerged areas. Per gallon they fill about the same joint volume, so coverage for the same tile is close.
When can I get Kerapoxy CQ wet?
The data sheet asks for 10 to 14 days of curing at 73°F before water immersion or exposure to chemicals, and at least 3 days before routine cleaning. Do not walk on it for 24 hours or allow heavy traffic for 48 hours. Cooler rooms need longer. Keep the tile and substrate between 60 and 90°F while grouting and for 72 hours afterward.
MAPEI and MAPEI Kerapoxy CQ are trademarks of their owner. This page is an independent estimate based on the published data sheet; check the bag label before mixing.