Garage Floor Coating Calculator: Epoxy Kits and Gallons

1. Set Floor size by to length x width and enter the floor length and width in feet, or switch to Area and type the floor area in square feet.
2. Pick the coating product. The calculator fills in its verified coverage; choose Smooth or Rough concrete to use the right end of the range. For Behr or any other brand, pick Custom and type the coverage from the can.
3. Set the number of coats, add an optional waste percent or a lower first-coat coverage for porous slabs, and read the kits, pouches or gallons to buy.

A garage floor coating calculator estimates how much epoxy or floor coating you need to cover a concrete garage floor. It turns the floor area and the number of coats into whole kits, pouches or gallons of product.

Floor coatings are sold two ways. Consumer epoxy and polycuramine come as a kit or burst pouch rated for a set area, while clear polyaspartic finishes are sold by the gallon. This tool handles both, and lets you enter any brand as Custom.

The amount depends on three things: how big the floor is, how many coats you plan, and how much area one container covers. That last figure, the coverage, is where products differ most, and where a porous slab can change the answer. For the paint-style version of this math, see the paint coverage calculator.

The calculator multiplies your floor area by the number of coats, then divides by the coverage of one kit or gallon and rounds up, because you can only buy whole containers.

When you enter a lower first-coat coverage, the calculator sizes each coat separately and adds them, because bare porous concrete soaks up more on the first pass than a sealed second coat does. A waste percent, if you add one, is applied to the area before the division.

1. Floor area. Length times width, in square feet (or your typed area).
2. Coverage. Set from the product and the smooth-or-rough surface, and editable for any brand.
3. Coats and waste. Multiply by coats, add any waste percent, or split out a porous first coat.
4. Round up. Divide by the coverage and round up to whole kits, pouches or gallons.

We do not publish a Behr coverage number because it is not readable on Behr's own current data sheet, so Behr is offered only as a Custom entry. See resin epoxy calculator for coating volume by thickness instead of by kit.

Take a two-car garage, 20 ft by 20 ft, coated with one coat of Rust-Oleum EpoxyShield water-based epoxy at 250 sq ft per pouch.

1. Floor area: 20 x 20 = 400 sq ft.
2. Pouches: 400 x 1 coat / 250 = 1.60, rounded up to 2 pouches.
3. Kit: two pouches is exactly one 2.5-car EpoxyShield kit (about 500 sq ft of rated coverage).
4. Porous slab: on rough or etched concrete, set a lower first-coat coverage or add 5 to 10 percent waste, which can push a borderline floor into a third pouch.

The same 400 sq ft floor needs 2 RockSolid pouches at the porous 200 sq ft end, or 2 one-gallon LD-2009 polyaspartic kits per coat at 275 sq ft per gallon on smooth concrete.

Four inputs move the answer, and coverage and porosity move it most.

Concrete Porosity

Bare, rough or acid-etched concrete drinks the first coat. Life Specialty rates LD-2009 at 250-300 sq ft per gallon on smooth concrete but only 200-250 on rough, a drop of up to a fifth. Use the Rough setting or a lower first-coat coverage when the slab is porous.

Number of Coats

Each coat multiplies the product needed. One-coat systems like EpoxyShield and RockSolid are sized for a single pass; polyaspartic and clear topcoats are often two coats.

Film Thickness

Coverage figures assume a recommended dry film thickness. EpoxyShield's 250 sq ft per pouch is quoted at 3.0 to 3.5 mils. Spreading it thinner stretches coverage but weakens the film; laying it thicker uses more.

Waste and Spillage

Roller soak-up, cut-in, and mixing losses add up. A 5 to 10 percent waste allowance covers most jobs; see the self-leveling calculator for how overage works on floor products.

The three chemistries differ in how they are sold, how many coats they need, and how they handle a porous slab.

RockSolid's resin is a proprietary blend of epoxy, urethane and polyurea, so it doubles as the polyurea-blend option. For a pure polyurea by volume, use the polyurea calculator. To understand two-part mixing before you pour, read epoxy resin mix ratio explained.

Buying a Kit for a 1-car or 2-car Garage

Enter the floor, pick EpoxyShield or RockSolid, and the Kit guide shows whether you need a 1-car kit (one pouch) or a 2.5-car kit (two pouches).

Adding a Clear Topcoat

Switch the product to LD-2009 polyaspartic, set two coats, and size the gallons for a finish over a cured base coat.

Pricing a Brand We Do Not List

Choose Custom, read the coverage off the Behr or other can, and get a kit or gallon count from your own number.

Checking a Porous or Etched Slab

Set the surface to Rough, or enter a lower first-coat coverage, to see how much more product a thirsty slab needs.

1. Ignoring the Porous First Coat

Bare concrete soaks up far more on coat one. Sizing every coat at the smooth-surface rate can leave you a pouch short mid-job.

2. Treating Polyaspartic as a Base Coat

LD-2009 is a clear finish applied over a cured base coat, not straight onto bare concrete. Plan a base plus topcoat, not polyaspartic alone.

3. Buying by Floor Area Without Matching Coverage

A 400 sq ft floor is not automatically one kit. Always divide by the product's own coverage and round up.

4. Borrowing a Coverage Number from Memory

Commonly quoted figures, including the Behr spread, often are not on the maker's current page. Read the coverage off your can and enter it as Custom.

5. Skipping Prep and Etching

Coverage and adhesion both assume a cleaned, etched slab. Skipping prep wastes product to poor bonding and peeling.

6. Rounding Containers Down

Kits, pouches and gallons are sold whole. 1.6 pouches means 2. Running out forces a cold joint or a color mismatch between batches.

The calculator uses each maker's own published coverage and rounds up to whole containers. Real coverage varies with slab condition, temperature and technique.

Figures are rounded for display. Always confirm against the current product data sheet and the coverage printed on the container you buy.

A typical 2-car floor is 400 to 500 sq ft. At Rust-Oleum EpoxyShield's ~250 sq ft per pouch, a 400 sq ft floor needs 2 pouches, which is one 2.5-car kit. Larger or porous floors may need a third pouch.

About 250 sq ft per pouch at the recommended 3.0 to 3.5 mils dry film, with a 15 percent material loss already assumed, per Rust-Oleum's ESH-39 data sheet. EpoxyShield is a one-coat system.

Kits or gallons equals floor area times the number of coats, divided by the coverage of one kit or gallon, rounded up. For a 400 sq ft floor, one coat at 250 sq ft per kit is 2 kits.

Rust-Oleum RockSolid covers 200 to 250 sq ft per kit in one coat. For a 400 sq ft floor that is 2 kits at the porous 200 sq ft end, or 2 kits at 250. Coverage drops on rougher concrete.

Life Specialty LD-2009 covers 250 to 300 sq ft per gallon on smooth concrete and 200 to 250 on rough. A 400 sq ft floor needs 2 one-gallon kits per coat on smooth, and polyaspartic is usually applied over a base coat.

Behr's coverage could not be read on Behr's own current data sheet, which sits behind a security wall. Rather than publish an unverified figure, we let you enter Behr as a Custom product using the coverage printed on the can.

Yes. Bare, rough or acid-etched concrete soaks up more on the first coat. Set the surface to Rough, add a waste percent, or enter a lower first-coat coverage so the first pass is sized separately.

EpoxyShield and RockSolid are designed as one-coat systems. Clear polyaspartic finishes and most topcoats are applied in two coats over a cured base. Set the coats input to match your system.

A 1-car bay is about 250 sq ft, which matches one EpoxyShield or RockSolid pouch (the 1-car kit). Measure your floor first; some single bays run larger and need the 2.5-car kit.

No. The calculation runs in your browser and nothing is sent to our servers. Anything you choose to Save stays in this browser only.

• Rust-Oleum EpoxyShield Water-based Epoxy Garage Floor Coating (Pouch Kits), TDS ESH-39: ~250 sq ft per pouch (Rust-Oleum, Form GDH-1219 Rev. 050418, read 2026-10-04).
• Rust-Oleum RockSolid Garage Floor Coating Kit (Polycuramine), TDS RSD-10: 200-250 sq ft per kit (Rust-Oleum, Form GDH-810 Rev. 080221, read 2026-10-04).
• Life Specialty Coatings LD-2009 Polyaspartic (Clear Sealers) TDS: 250-300 smooth / 200-250 rough sq ft per gallon (Life Specialty Coatings, updated March 2025, read 2026-10-04).
• BEHR PREMIUM 1-Part Epoxy Concrete and Garage Floor product page (coverage not verifiable; page behind a security wall on 2026-10-04) (Behr, unreachable on 2026-10-04; left as Custom input).