Epoxy Calculator
Calculate the exact amount of epoxy resin and hardener for any rectangular or circular surface. Get volume in gallons, fluid ounces, and the precise 2:1 resin-to-hardener mix ratio.
About This Calculator
The Epoxy Resin Calculator helps DIY enthusiasts, woodworkers, and contractors determine the exact volume of epoxy resin and hardener needed for coating any surface. Whether you are building an epoxy river table, coating a garage floor, or sealing a countertop, this tool provides precise material estimates to avoid waste and ensure you buy the right amount.
The calculator supports two surface shapes: rectangular (tables, floors, countertops) and circular (round tables, decorative pieces, art projects). Simply enter the surface dimensions and desired coating thickness to get the total epoxy volume in cubic inches, US gallons, and US fluid ounces. The calculator also breaks down the total into the required resin and hardener amounts based on the standard 2:1 epoxy mix ratio by volume.
The underlying formula is straightforward. For rectangular surfaces, total volume = length × width × coating thickness. For circular surfaces, total volume = π × radius² × coating thickness. The result is then converted to gallons (÷ 231) and fluid ounces (÷ 1.80469) for practical purchasing. The 2:1 resin-to-hardener ratio means two-thirds of the total volume is resin and one-third is hardener.
Regional Notes
The calculator uses US customary units (inches, gallons, fluid ounces) which are standard for epoxy resin measurements in the US and commonly used internationally. In the UK and India, epoxy is also typically sold in fluid ounces or liters; the fluid ounce output provides a direct purchasing reference. For metric conversions, 1 US fluid ounce = 29.5735 mL, so multiply the fluid ounce result by 29.5735 to get milliliters.
Frequently Asked Questions
What is the formula for calculating epoxy resin?
For rectangular surfaces, epoxy volume = length x width x coating thickness. For circular surfaces, epoxy volume = π x radius² x coating thickness. Convert the result from cubic inches to gallons by dividing by 231, or to fluid ounces by dividing by 1.80469.
What is the epoxy resin to hardener ratio?
Epoxy resin mixes with hardener in a 2:1 ratio by volume — two parts resin to one part hardener. This means two-thirds of the total epoxy volume is resin and one-third is hardener.
How long does epoxy flooring last?
Residential epoxy flooring can last at least ten years with proper care. Longevity depends on floor material strength, prior surface treatment, epoxy coating quality and thickness, and pressure on the surface over time.
Can I use epoxy on any surface?
Epoxy bonds well with most materials including metal, plastic, glass, ceramic, wood, and rubber. However, the surface must be clean and grease-free for proper adhesion. Porous surfaces may require a primer coat.
How do I convert epoxy volume from cubic inches to gallons?
To convert cubic inches to US gallons, divide the volume by 231 (since 1 US gallon = 231 cubic inches). For US fluid ounces, divide the cubic inches by 1.80469 (since 1 US fluid ounce = 1.80469 cubic inches).
What coating thickness should I use for epoxy?
Typical epoxy coating thickness ranges from 1/8 inch (0.125 in) for thin applications up to 2 inches for deep pour table tops. For floors, 1/8 to 1/4 inch is common. Thicker coatings provide more durability but require more material and longer curing time.