Epoxy Resin Calculator

The Epoxy Resin Calculator tells you exactly how much epoxy to buy for your project — whether you are pouring a river table, casting a deep mold, flooding a table top, or filling a round mold. Enter your dimensions and it works out the total mixed volume in gallons and liters, splits it into resin and hardener for your mix ratio, estimates the mixed weight and coverage, and adds a waste buffer so you never run short in the middle of a pour.

How Much Epoxy Resin Do I Need?

The amount of epoxy you need is simply the volume of the space you are filling. For a rectangular pour that is length × width × depth; for a round mold it is π × radius² × height. Once you have the volume, convert it to gallons or liters and split it into resin and hardener. This calculator handles every step and adds a margin for waste.

Epoxy Resin Formula

Useful conversions: 1 US gallon = 231 cubic inches = 3,785 cm³ = 128 fluid ounces, and 1 liter = 1,000 cm³. Mixed epoxy weighs about 1.1 g/cm³, so a gallon weighs roughly 9–9.5 lb.

Epoxy Coverage Chart (per US gallon)

For coatings and flood coats, thickness sets how far a gallon goes. Thinner coats cover much more area:

Understanding Epoxy Mix Ratios

Epoxy is a two-part system: resin (Part A) and hardener (Part B). The mix ratio tells you how much of each to combine. A 2:1 ratio means two parts resin to one part hardener — so of your total, two thirds is resin and one third is hardener. Common ratios are 2:1, 1:1, 3:1, 4:1, and 5:1, and they are usually specified by volume. Getting the ratio right is critical: too much or too little hardener leaves the cure soft, tacky, or bendy. Always measure carefully and mix thoroughly.

Deep Pour vs Table-Top (Coating) Epoxy

How to Use This Calculator

1. Choose your project type: River Table / Deep Pour, Flood Coat / Table Top, or Round Mold, then select Imperial (inches) or Metric (cm).
2. Enter your dimensions: Length, width, and depth for rectangular pours; diameter and height for round molds. For a river channel, set the fill-area percentage in Advanced options.
3. Set the mix ratio and waste buffer: Pick your kit's ratio (e.g. 2:1) and keep the default 10% buffer, or adjust it. Add a price to see an estimated cost.
4. Click Calculate: Review the total volume, the resin and hardener amounts, the mixed weight, coverage area, and a full step-by-step breakdown.

Frequently Asked Questions

How much epoxy resin do I need?

Multiply the area you are filling by the pour depth to get the volume, then convert to gallons or liters. For a rectangular pour, volume equals length × width × depth. This calculator does the math for you and adds a waste buffer so you do not run short.

How do I split epoxy into resin and hardener?

Divide the total mixed volume by the mix ratio parts. For a 2:1 kit there are 3 total parts, so resin is two thirds and hardener is one third of the total. This tool splits the total automatically for 2:1, 1:1, 3:1, 4:1, and 5:1 ratios.

How many square feet does a gallon of epoxy cover?

At a 1/8 inch flood-coat thickness, one US gallon of epoxy covers about 12 to 13 square feet. At 1/16 inch it covers about 25 square feet, and at 1/4 inch about 6 square feet. Coverage is simply the gallon volume divided by the coat thickness.

How thick can I pour epoxy in one layer?

Standard table-top or coating epoxy should be poured in thin 1/8 inch layers to avoid overheating. Deep-pour casting epoxy is formulated for thick pours and can typically be poured 1 to 2 inches, and up to several inches, in a single layer. Always follow the manufacturer maximum pour depth.

How much does epoxy resin weigh?

Cured epoxy has a density of roughly 1.1 grams per cubic centimeter, so a US gallon of mixed epoxy weighs about 9 to 9.5 pounds, and a liter weighs about 1.1 kilograms. This calculator estimates the mixed weight from your volume.

Should I add extra epoxy for waste?

Yes. Some resin always clings to the mixing cup and stir stick, and pours can seep under molds or into wood grain. A 5 to 10 percent buffer is a safe margin, and this calculator includes 10 percent by default.

Additional Resources

• Epoxy - Wikipedia
• Volume - Wikipedia