Epoxy Floor Coating Calculator: How Much Epoxy You Need, Coverage per Gallon, and Surface Prep
How many gallons and kits a floor takes, coat by coat, from the square footage and the product data sheet; what mils, solids, and square feet per gallon mean; which concrete surface profile each coating needs; and whether to grind or shot blast to get it. HTS Poly and Ameripolish epoxies, polyaspartics, and urethanes; grinders from 120-volt single-head to 30-inch propane planetary, shot blasters, and scarifiers in the rental fleet.
Estimate coating material
Enter the floor area, pick a primer, build coat, and topcoat by type, and get gallons and kits per layer, the film build, and what the system needs before the first coat goes down. Each type starts at a typical square-feet-per-gallon rate; type the number from your product's data sheet over it.
Estimate coating material
Primer, build coat, topcoat · gallons, kits, film build, and the prep the system needsMaterial
—
| Layer | Sq ft/gal | Gal | Typical kits |
|---|
Planning figure. Profile depth, porosity, temperature, and technique move real coverage 20% either way; kit sizes vary by brand, and the counter rounds to the product you order.
Square feet per gallon by film thickness and solids
Dry film in mils down the side, solids by volume across. Square feet per gallon = 1,604 × solids ÷ dry mils, no waste. Layers with a known solids figure are highlighted.
Wet film is the dry film divided by the solids: a 50% solids coating at 4 dry mils goes on at 8 wet mils and covers 200 square feet per gallon.
How coating coverage works
A US gallon is 231 cubic inches. Spread 1 mil (one thousandth of an inch) thick, it covers 1,604 square feet. That single number turns any data sheet into gallons:
Square feet per gallon = 1,604 × solids by volume ÷ dry film thickness in mils.
A 100% solids epoxy laid at 10 mils covers 160 square feet per gallon, which is why HTS publishes 150 to 200 for EPX-100: 8 to 10.7 mils per coat. A urethane topcoat spread at 4 wet mils covers 400, which is the figure on the MCU sheet. A 20-mil vapor barrier coat is 80 square feet per gallon, and the EPX-MVB FS sheet says exactly that.
Wet film is what you measure with a comb gauge as you roll; dry film is what's left after the solvent or water leaves. For 100% solids products they're the same. For a water-based epoxy or a urethane, the wet film is the dry film divided by the solids.
The range on a data sheet is real. A CSP 3 shot-blasted floor has more surface than a CSP 2 ground floor and takes more material to fill the texture; a broom finish takes more still; a sanded recoat takes the least. Plan at the low end of the range for bare concrete and keep the high end for recoats. Sealers and penetrating products work the same way but on thinner or no film; they get their own pages.
Coverage, pot life, and return to service by product
The calculator works by type; this is where the brand numbers live. Figures from the HTS Poly and Ameripolish technical data sheets. Coverage is for bare prepped concrete; the second figure, where there is one, is for a recoat over an existing coating. Mils per coat are back-calculated with the 1,604 rule; "wet" marks products whose solids aren't published. Type the data-sheet rate into the calculator's square-feet-per-gallon field to estimate a specific product.
Primers and vapor barriers
| Product | What it is | Sq ft/gal | Mils per coat | Pot life | Recoat | Traffic | Sizes |
|---|---|---|---|---|---|---|---|
| HTS PMR-100 | High-solids epoxy primer for porous or old concrete | 200–250 | 6.4–8 wet | 30–40 min | 8 h | full cure 7 d | 1.5, 3 gal kits |
| HTS EPX-MVB FS | 100% solids moisture vapor barrier epoxy, tested at 20 mils | 80–90 | 18–20 | 12–15 min | 3–6 h | — | 1.5, 3 gal kits |
| Ameripolish MVB | 89% solids moisture vapor barrier epoxy primer; CSP 3 minimum | 100 at 16 mils | 14 dry | 45 min working time | 6–12 h | — | 3 gal kit |
Epoxy build and color coats
| Product | What it is | Sq ft/gal | Mils per coat | Pot life | Recoat | Traffic | Sizes |
|---|---|---|---|---|---|---|---|
| HTS EPX-100 HV | 100% solids high-viscosity epoxy, the build coat under a topcoat or on its own | 150–200 | 8–10.7 | 30–40 min | 8 h | foot 16 h, heavy 48 h, full 7 d | 1.5, 3 gal kits |
| HTS EPX-60 WB | Water-based epoxy for occupied buildings; under 50 g/L VOC | 200–250 | 6.4–8 wet | 45–50 min | 10–24 h | foot 16 h, full 5–7 d | 1, 4 gal kits |
Topcoats
| Product | What it is | Sq ft/gal | Mils per coat | Pot life | Recoat | Traffic | Sizes |
|---|---|---|---|---|---|---|---|
| HTS PAS-100 | 100% solids aliphatic polyaspartic, fast; UV stable, interior and exterior | 150–200 (recoat 200–250) | 8–10.7 | 10–15 min | 8 h | foot 4–6 h, full 24 h | 1.5, 3 gal kits |
| HTS PAS-200 | Same chemistry with working time for larger floors | 150–200 (recoat 200–250) | 8–10.7 | 12–18 min | 8 h | foot 10–12 h, full 48 h | 1.5, 3 gal kits |
| Ameripolish Polyaspartic 85 | High-solids polyaspartic topcoat, clear or colored; 6–12 mils, 15 max | 125–250 | 6–12 | 30–45 min | when tack-free | foot 2–4 h, vehicles 24–48 h | 2, 10 gal kits |
| HTS MCU-HG / MCU-MT | One-component moisture-cure aliphatic urethane, gloss or matte, clear or color pack; 4 mils max per coat | 400–500 (recoat 600–700) | ≤4 wet | 40–45 min | 10–30 h | — | 1 gal |
This page is conformal coating systems. Acrylic and penetrating sealers for driveways, pool decks, and broom-finished or stamped concrete (HTS CS-AC30, Ameripolish X-Link, DNS-400, AquaShield) are on the exterior coatings page; densifiers, stain protectors, guards, and dyes are on the polished concrete page. Conditions common to these coatings: concrete at least 28 days old; moisture vapor under 3 lb/1,000 sq ft/24 h (ASTM F1869) or 5% on a meter; 50 to 85°F and 20 to 60% humidity; no wet cleaning the day of. Pot life and cure are at 72 to 77°F.
Typical systems
| Floor | System | Build | Notes |
|---|---|---|---|
| Garage, shop, showroom | EPX-100 HV + PAS-100 or PAS-200, or + Polyaspartic 85 | ~18–20 mils | Epoxy for build and bond, polyaspartic for UV, hot tires, and chemical resistance. |
| Warehouse, light industrial, fast return | PMR-100 + EPX-100 HV, or two coats of EPX-100 HV | ~18–22 mils | Primer when the slab is porous or old; forklift traffic at 48 hours. |
| Slab that fails the moisture test | EPX-MVB FS or Ameripolish MVB + EPX-100 HV + topcoat | ~36–40 mils | The vapor barrier coat is the budget: 80 to 100 square feet per gallon. Ameripolish MVB wants CSP 3. |
| Occupied building, low odor | EPX-60 WB × 2, or EPX-60 WB + MCU topcoat | ~8–12 mils | Water-based, under 50 g/L VOC; a finish, not a repair. |
How much epoxy for a garage floor
The usual system: one coat of 100% solids epoxy at 160 square feet per gallon under one coat of polyaspartic at 225, with 10% waste, on bare ground concrete. Run your own footage through the calculator above; a porous slab, a step, or an island changes it.
| Floor | Sq ft | Epoxy | Polyaspartic | Total | Typical kits |
|---|---|---|---|---|---|
| 1-car garage | 250 | 1.7 gal | 1.2 gal | 2.9 gal | Epoxy 1 × 3 gal · polyaspartic 1 × 1.5 gal |
| 2-car garage | 440 | 3.0 gal | 2.2 gal | 5.2 gal | Epoxy 1 × 3 gal + 1 × 1.5 gal · polyaspartic 1 × 3 gal |
| 3-car garage | 650 | 4.5 gal | 3.2 gal | 7.6 gal | Epoxy 1 × 3 gal + 1 × 1.5 gal · polyaspartic 1 × 3 gal + 1 × 1.5 gal |
| 24 × 36 shop | 864 | 5.9 gal | 4.2 gal | 10.2 gal | Epoxy 2 × 3 gal · polyaspartic 1 × 3 gal + 1 × 1.5 gal |
| 30 × 40 shop | 1,200 | 8.3 gal | 5.9 gal | 14.1 gal | Epoxy 3 × 3 gal · polyaspartic 2 × 3 gal |
| Small warehouse bay | 2,500 | 17.2 gal | 12.2 gal | 29.4 gal | Epoxy 6 × 3 gal · polyaspartic 4 × 3 gal + 1 × 1.5 gal |
Kits shown are the common 1.5 and 3 gallon sizes. Two coats of epoxy and no topcoat is about the same material; a vapor-barrier primer roughly doubles it.
Polyaspartic vs epoxy
Most floors get both: epoxy underneath because it wets into the concrete, builds thick, and is cheaper per mil; polyaspartic on top because it doesn't yellow, shrugs off hot tires and chemicals, and reopens the floor the same day. The questions are which one goes where, and whether one of them can do the whole job.
| 100% solids epoxy (EPX-100 HV) | Polyaspartic (PAS-100, PAS-200, Polyaspartic 85) | |
|---|---|---|
| Build per coat | 8–11 mils; self-levels into the profile | 6–12 mils; thin and fast, 15 mils max |
| Pot life at 72°F | 30–40 minutes | 10–15 minutes (PAS-100), 12–18 (PAS-200), 30–45 (Poly 85) |
| Return to service | Foot traffic 16 h, heavy 48 h, full cure 7 days | Foot traffic 2–6 h, vehicles 24–48 h |
| UV | Ambers and chalks in sunlight; keep it under a topcoat near doors | Aliphatic: stays clear and colorfast outdoors |
| Hot tires, chemicals | Good; hot-tire pickup is the classic failure of thin epoxy | Better; the reason it's the topcoat |
| Bond to bare concrete | Excellent; the primer of choice | Good; HTS prefers an epoxy primer under it for build and adhesion |
| Working temperature | 50–85°F | 50–85°F; cold slows it, heat shortens an already short pot life |
| Cost per mil | Lower | Higher |
| Use it alone when | Interior, no direct sun, budget floor, forklift warehouse that can wait 48 hours | Fast turnaround, exterior or sun exposure, thin decorative system over sound concrete |
Surface profile: which CSP the coating needs, and which machine makes it
ICRI's Concrete Surface Profile scale runs from 1 (nearly flat, acid-etched) to 10 (exposed coarse aggregate). Thin coatings need a fine profile so they don't bridge peaks and leave pinholes; thick coatings and overlays need texture to key into. Every HTS floor coating specifies CSP 2–3 on bare concrete, which is the range a diamond grinder or a light shot blast produces. Under a film-forming (conformal) coating, acid etching is not a substitute: it leaves CSP 1, no mechanical key, and salts in the pores unless it is neutralized and rinsed completely, which then means a wet slab. Etching does have a place under penetrating and semi-penetrating products: water repellents, penetrating sealers, stains, and guards on dense troweled concrete, where the job is to open the pores rather than cut a key. Those products, and the chemical etchers made for them, are on the exterior coatings and polished concrete pages.
| CSP 1 | CSP 2 | CSP 3 | CSP 4 | CSP 5 | CSP 6 | CSP 7 | CSP 8 | CSP 9 | CSP 10 |
|---|---|---|---|---|---|---|---|---|---|
| acid etch | grind | light shot blast | medium shot blast | medium-heavy shot blast | heavy shot blast | heavy scarify | scabble | heavy scabble | exposed aggregate |
Highlighted: the range the coatings on this page call for.
By coating thickness (ICRI 310.2R)
| Coating or overlay | Dry film | CSP |
|---|---|---|
| Sealers | 0–3 mils | 1–3 |
| Thin-film coatings | 4–10 mils | 2–4 |
| High-build coatings | 10–40 mils | 3–5 |
| Self-leveling toppings | 50 mils–1/8" | 4–6 |
| Polymer overlays | 1/8"–1/4" | 5–9 |
The coating data sheet governs where it names a number; HTS names CSP 2–3 for everything on this page.
By preparation method
| Method | CSP produced | Rent it |
|---|---|---|
| Acid or chemical etching | 1 | Not under a conformal coating. Acceptable before penetrating sealers, water repellents, stains, and guards where their data sheets allow it |
| Diamond grinding | 1–3 | Planetary grinders from 120 V single-head to 30" 480 V and propane machines, with 16–30 grit metal-bond tooling; 7" edger for the perimeter |
| Shot blasting | 2–9 by shot size and speed | Walk-behind shot blaster; fastest prep on open floors |
| Scarifying | 4–9 | Scarifier with carbide cutters; coating removal and heavy profile |
| Scabbling / needle scaling | 5–9 | Pneumatic; patches and edges |
| Water jetting | 3–10 | Specialty contractor |
Pair any dry method with a HEPA extractor; OSHA Table 1 requires it indoors.
Grinder or shot blaster
Both reach CSP 2–3. They get there differently, and the floor usually decides.
| Diamond grinder | Shot blaster | |
|---|---|---|
| Profile | CSP 1–3 by tooling: 16–30 grit metal-bond for CSP 2–3, finer for a polish | CSP 2–9 by shot size and travel speed; CSP 3 is the natural result |
| What it removes | Thin coatings, sealers, curing compound, paint, laitance, high spots. Thick or gummy coatings load the tooling | Laitance, curing compound, light coatings. Thick coatings and mastics gum up the shot; scarify those first |
| Flatness | Flattens: knocks down ridges and trowel marks, which a thin coating will otherwise telegraph | Follows the floor; a wavy slab stays wavy |
| Edges and corners | To within 1/4" with a 7" edger | Leaves a 2–4" band at walls and columns that still needs the grinder |
| Surface it leaves | Smooth and uniform; on hard, steel-troweled slabs it can polish instead of profile unless the tooling is coarse enough | Uniform open texture that coatings key into; shot lines can show through thin clear sealers |
| Dust | Dry with a HEPA extractor (OSHA Table 1); wet grinding is an option on exterior work | Closed loop: the shot is recycled and the dust goes to the attached collector |
| Consistency and skill | Forgiving. The profile comes from the tooling grit and the number of passes, so two operators get the same floor. The mistakes are dwelling in one spot, which leaves swirl marks, and tooling too fine for a hard slab, which polishes instead of profiles | Operator-dependent. Travel speed, shot flow, shot size, and pass overlap all set the profile. Rows that don't overlap evenly leave "cornrows" (tiger stripes) that telegraph through a light coating; too slow or stopped with the shot on cuts a deeper band; a damp slab or gummy coating clogs the shot. Overlap passes about 50%, keep the speed constant, and run a test patch first |
| Speed | Slower per pass; usually two passes | Fastest prep per square foot on open floors, once the operator has the settings dialed in |
| Power and access | 120 V single-head machines for small rooms and garages; planetary machines up to 30" wide on 480 V three-phase or propane for open floors. Propane runs where there's no power, with ventilation | 230 or 480 V three-phase, or gas; needs a straight run and room to turn |
| Choose it for | Garages, small rooms, floors with old coatings or sealers, slabs that need flattening, thin coatings and clear sealers; with a 30" planetary machine, open floors too | Large open warehouses and shops, high-build or vapor-barrier systems that want CSP 3, floors with no coating to remove |
Most big jobs use both: the blaster for the field, the grinder and edger for the perimeter, columns, and anything the blaster won't fit. A thick old coating or mastic gets a scarifier first, then a grinder to take the ridges down to CSP 3; scarifying alone leaves too rough a surface for a 10-mil coating.
If the crew hasn't run a shot blaster before, the grinder is the safer rental: it is slower, but the result doesn't depend on walking speed, and a grinder pass can also fix a blasted floor that came out striped. A blaster earns its speed on long open runs where the operator can hold one speed and one overlap from wall to wall.
Moisture, temperature, and the recoat window
Moisture is what kills epoxy floors. Test every slab: calcium chloride (ASTM F1869) under 3 lb per 1,000 square feet in 24 hours, or in-slab relative humidity (ASTM F2170). Over that, the system starts with a moisture vapor barrier epoxy, tested at 16 to 20 mils, or the floor waits. New concrete needs 28 days minimum. Don't wet-clean a floor the day it's coated; the data sheets say so for every product.
Temperature runs 50 to 85°F for every HTS coating, slab and air, with humidity between 20 and 60%. Pot life is quoted at 72°F: PAS-100 at 10 to 15 minutes means mix one kit at a time and have the roller moving. Cold stretches every cure time on the table above; a 50°F slab can double them.
Recoat windows are the time after which the next coat still bonds chemically: 8 hours for the epoxies and polyaspartics, 10 to 30 hours for the urethanes. Past the window, sand with 120 to 220 grit, vacuum, and keep going. Plan the layers so each coat lands inside the previous one's window and the job finishes in a day or two instead of a week of sanding.
Questions we get at the counter
How much epoxy do I need for a 2-car garage?
How much epoxy do I need for a 2-car garage?
Call it 440 square feet. One coat of 100% solids epoxy at 150 to 160 square feet per gallon is about 3 gallons with waste: a 3-gallon kit plus a 1.5. A polyaspartic topcoat at 200 to 225 is another 2.2 to 2.4 gallons, so a 3-gallon kit. Run your own footage through the calculator; islands, a step, and a porous slab all change it.
Do I need a primer?
Do I need a primer?
On a sound, dense, ground slab a 100% solids epoxy bonds without one. Prime with PMR-100 when the concrete is porous, old, or dusty, when you want a higher build without a third coat of EPX-100, or when you're not sure. A vapor barrier primer is a different decision, made by the moisture test, not by preference.
Can I coat over the old epoxy?
Can I coat over the old epoxy?
If it's bonded (it doesn't flake at a scored X or lift under tape), sand it with 120 to 220 grit, vacuum, solvent-wipe, and coat; use the recoat coverage figure. If it's peeling anywhere, it's coming off everywhere eventually: grind or scarify it to bare concrete and start at CSP 2–3.
Can I just acid etch instead of grinding?
Can I just acid etch instead of grinding?
Not under these coatings. Etching leaves CSP 1 with no mechanical key, doesn't remove curing compound or sealers, and leaves salts in the pores unless it's neutralized and rinsed perfectly, which then means a wet floor. A rental grinder does a garage in a morning and the coating stays down.
How soon can I drive on it?
How soon can I drive on it?
PAS-100: foot traffic in 4 to 6 hours, full cure in 24. PAS-200: 10 to 12 hours and 48. EPX-100 HV: foot traffic in 16 hours, heavy traffic at 48, full cure at 7 days. Hot tires and a wet slab are the two things that lift a new floor; give it the full cure before parking a car that just came off the highway.
What grinder do I rent for a garage?
What grinder do I rent for a garage?
A walk-behind planetary grinder with 16 to 30 grit metal-bond diamonds, a HEPA extractor, and a 7-inch edger with a cup wheel for the walls and corners. It takes off the old sealer and profiles the slab in the same passes. Rent the three together and the tooling comes with it.
How much does it cost to epoxy a garage floor?
How much does it cost to epoxy a garage floor?
Doing it yourself, the cost is the material by the kit, the grinder rental for a day, and the tooling. Send the footage and the system through the form and the quote comes back with both. A contractor's price adds labor and margin on top; the material and prep are the same.