Estimate Epoxy Before You Mix The First Batch
Use this Concrete Epoxy Calculator to estimate epoxy coating, primer, build coat, topcoat or epoxy mortar material for concrete floors, garages, basements, workshops, patios and repair areas. Calculate square footage, total coated area, gallons or liters, kits, waste allowance and optional material cost using the actual coverage or yield published for your epoxy system.
Estimate a single coating, a full multi-coat system, known-area kits/gallons, or epoxy mortar volume for repairs and buildup.
Enter floor dimensions, coats, coverage rate, kit size and waste allowance.
Use manufacturer coverage for your application
Planning estimate only. Confirm product mixing ratio, pot life, recoat window, substrate preparation, temperature limits, moisture limits, film thickness and coverage using the manufacturer's current technical data and safety data sheet.
Estimate primer, build coat and topcoat separately using different coverage rates.
Convert an existing square-foot takeoff directly into gallons and whole kits.
Estimate epoxy mortar or filled-resin volume for rectangular repair areas or build sections.
Use mixed yield of the repair system
Use only for systems intended for the repair geometry and thickness involved. Many epoxy coatings are not designed for deep fills; epoxy mortar or aggregate-filled systems may have different mix ratios, lift limits and yields.
A Concrete Epoxy Calculator turns floor area and product coverage into a material estimate. For a basic coating, the calculator multiplies length by width to find square footage, multiplies that area by the number of coats, applies any selected waste or surface-profile allowance, and divides by the coverage rate entered in square feet per gallon.
The kit estimate then divides the required gallons by the mixed gallons supplied by one kit and rounds up to the next whole kit. This is important because two-component epoxies are usually packaged in fixed resin-and-hardener quantities that must be mixed according to the manufacturer's stated ratio.
The multi-coat calculator treats primer, build coat and topcoat independently because each layer can have a different coverage rate. The repair-volume mode uses geometry instead of coverage rate, converting the repair volume into gallons and then dividing by the mixed yield per kit.
Coverage should come from the selected product's current technical data.
The calculator rounds up to whole kits.
One U.S. gallon contains 231 cubic inches.
Calculate garage, basement, workshop and commercial floor square footage.
Estimate primer, build coat and topcoat separately when coverage rates differ.
Convert total gallons into whole mixed kits using your actual package size.
Estimate thicker epoxy mortar or filled-resin repair volumes from geometry.
Two floors with the same square footage can require different amounts of epoxy. Coverage depends on the thickness at which the product is applied, surface porosity, concrete profile, roller or squeegee method, broadcast aggregate, temperature, product solids and whether the coating is used as a primer, build coat or finish coat.
A smooth, dense slab may use material differently from a heavily shot-blasted or mechanically profiled slab. Cracks, bugholes, spalls and low areas can also consume material before a uniform coating thickness is achieved. That is why the calculator does not hard-code one coverage rate for all epoxy products.
For a rectangular floor, multiply length by width. A 24 ft × 20 ft garage contains 480 square feet. If a two-coat system uses the same product for both coats, the total coated area becomes 960 square feet before any surface-profile or waste allowance.
For L-shaped garages or workshops, divide the floor into rectangles and add the areas. Subtract permanent openings or areas that will not receive coating. Vertical stem walls, curbs, stairs and wall bases should be measured separately because they add coating area beyond the flat floor.
Calculate only the concrete surfaces that will actually receive epoxy.
Identify primer, build coat, broadcast and topcoat layers.
Use product coverage at the intended film thickness.
Account for profile, edges, mixing losses and field conditions as appropriate.
Plan whole kits while respecting the manufacturer's mixing ratio.
The total coat area is 480 × 2 = 960 square feet. At 250 square feet per gallon, the theoretical requirement is 3.84 gallons. With a 10% allowance, adjusted coat area is 1,056 square feet and the estimate becomes approximately 4.22 gallons.
With no allowance, 1,000 ÷ 300 = 3.33 gallons. If the epoxy is sold in 2-gallon kits, 3.33 ÷ 2 = 1.67 kits, so the purchase quantity rounds up to two kits.
If a 500-square-foot floor uses primer at 300 ft²/gal, build coat at 200 ft²/gal and topcoat at 350 ft²/gal, each layer is calculated independently. This is more accurate than averaging the three coverage rates because each layer has a different material build.
Four feet equals 48 inches. The repair volume is 48 × 6 × 1 = 288 cubic inches. Dividing by 231 gives approximately 1.25 gallons of theoretical mixed volume before any void or waste allowance.
Many concrete epoxy systems use more than one layer. A primer may be applied at a relatively high coverage rate to wet the prepared concrete. A build coat may be applied thicker and therefore cover fewer square feet per gallon. A topcoat can have a different resin chemistry, solids content and coverage again.
Broadcast systems can also include decorative flakes, quartz or aggregate. The amount of broadcast media is not calculated by this page because broadcast rates are normally stated in pounds per square foot or similar units and depend on whether the system uses a light, medium or full broadcast.
Coverage and film thickness are connected. If a coating is applied thicker, one gallon covers fewer square feet. Manufacturers may publish wet-film thickness, dry-film thickness or theoretical coverage at a stated mil thickness. Do not increase the coverage rate merely to make the calculated quantity smaller.
A “mil” is one-thousandth of an inch. Coating specifications can use mils to describe film build. The actual relationship between wet and dry film depends on product solids and chemistry, so the product data sheet should control.
Epoxy performance depends heavily on surface preparation. The concrete should be evaluated for contamination, weak surface material, laitance, previous coatings, moisture, cracks and the profile required by the coating system. Mechanical preparation such as grinding or shot blasting is common for many professional systems, but the correct method depends on the product and project.
A calculator cannot determine whether concrete is ready to coat. The substrate may require repair, cleaning, profiling or moisture testing before epoxy is mixed. Applying epoxy over a poorly prepared surface can cause delamination even when the material quantity is correct.
Concrete moisture can affect epoxy adhesion and blistering risk. Some coating systems have strict limits for moisture vapor emission or relative humidity, while other products are designed for higher-moisture conditions. Do not assume that a dry-looking surface is suitable.
Use the testing method and acceptance criteria required by the epoxy manufacturer or project specification. Quantity calculations do not replace moisture evaluation.
Two-component epoxy begins reacting after resin and hardener are mixed. Pot life can shorten as material temperature or batch mass increases. A large mixed batch can generate more heat and cure faster than the same material spread across a floor.
The total gallons calculated for a project should therefore not be mixed all at once unless the product instructions specifically allow it. Divide the project into manageable batches based on crew size, application method and the manufacturer's stated pot life and recoat window.
Epoxy resin, hardeners, solvents and additives can present skin, eye, inhalation or sensitization hazards depending on the product. Read the label and Safety Data Sheet before use. Wear the personal protective equipment specified for the system and provide ventilation appropriate to the product and work area.
OSHA's Hazard Communication requirements address labels and Safety Data Sheets for hazardous chemicals in workplaces. Product-specific instructions should control handling, storage, mixing, spill response and disposal.
A resin-based coating system that can provide chemical resistance, abrasion resistance, decorative finish and higher film build than ordinary paint, depending on product.
Concrete paint may use a different binder and film build, while a cementitious overlay adds a new mineral-based surface layer. Their quantity formulas and preparation requirements can be very different from epoxy.
Each layer can use a different amount of material, so primer, build coat and topcoat should be checked separately.
Common questions about epoxy coverage, gallons, kits, floor coatings, multiple coats and repair volume.