Epoxy Calculator

Introduction

Epoxy resin is a popular material used in construction, crafts, and woodworking. It creates a strong, clear, and waterproof coating or fill. However, buying too much or too little epoxy can waste money or leave your project unfinished. That's why knowing the right amount before you start is so important.

This Epoxy Calculator helps you figure out exactly how much epoxy resin you need for your project. Simply enter the size of your surface and the thickness you want, and the tool does the math for you. It works for both flat surfaces, like tabletops and counters, and circular surfaces, like round molds or coasters. You can also enter the price per gallon or ounce to get a cost estimate. The calculator supports both imperial and metric units, so no matter how you measure, you'll get a quick and accurate result.

How to Use Our Epoxy Calculator

Enter the size of your surface and the price of your epoxy resin. The calculator will tell you the volume of the space, how much epoxy resin you need, and what it will cost.

First, choose your surface shape. Select the Flat Surfaces tab for rectangular areas like countertops or tabletops, or select the Circular Surfaces tab for round areas like circular table tops or coasters.

Width – For flat surfaces, enter the width of the area you want to cover. Pick your unit of measurement from the dropdown menu (feet, inches, yards, centimeters, or meters). If you need help determining the area of your surface, try our Square Footage Calculator.

Length – For flat surfaces, enter the length of the area you want to cover. Pick your unit of measurement from the dropdown menu.

Diameter – For circular surfaces, enter the full diameter (the distance across the circle) of the round area. Pick your unit of measurement from the dropdown menu.

Thickness – Enter how thick you want the epoxy layer to be. This is the depth of resin you plan to pour. Pick your unit of measurement from the dropdown menu.

Cost – Enter the price of your epoxy resin per unit of volume. Use the dropdown to choose whether the price is per gallon, per ounce, per liter, or per milliliter.

Click the Calculate button to see your results. You can switch between Imperial and Metric in the results section to view the output in your preferred units. Press Reset to clear your inputs and start over.

What Is Epoxy Resin?

Epoxy resin is a strong, liquid material that hardens into a tough, clear, or colored coating. It is made by mixing two parts together: the resin and the hardener. Once combined, a chemical reaction starts that turns the liquid into a solid. Epoxy is popular in construction, woodworking, crafting, and flooring because it creates a durable, waterproof surface that resists scratches and chemicals.

How Much Epoxy Resin Do You Need?

Figuring out how much epoxy to buy is one of the most important steps before starting a project. If you buy too little, you won't be able to finish the job. If you buy too much, you waste money. The amount of epoxy you need depends on three things: the surface area you want to cover, the thickness of the coating, and the shape of the surface.

For flat surfaces like tabletops, countertops, or floors, you multiply the width by the length by the desired thickness to get the volume. For circular surfaces like round tables or coasters, you use the diameter and thickness to calculate volume using the circle area formula (π × radius² × thickness).

Epoxy Thickness Guidelines

Most epoxy coatings range from a thin seal coat of about 1/16 inch to deep pours of 1 to 2 inches or more. Thin coats work well for sealing wood or adding a glossy finish. Thicker pours are used for river tables, molds, and casting projects. Keep in mind that many epoxy products have a maximum pour depth per layer. Pouring too thick in one go can cause the epoxy to overheat, turn yellow, or crack. Always check the manufacturer's instructions for the recommended pour depth.

Estimating Epoxy Cost

Epoxy resin is typically sold by the gallon or by the ounce. Prices vary widely based on the brand, quality, and type of epoxy. General-purpose epoxy costs around $40 to $80 per gallon, while specialty or UV-resistant formulas can cost more. This calculator lets you enter the price per unit so you can estimate your total material cost before you start shopping.

Tips for Working with Epoxy

• Always mix extra. It's smart to add about 10% more epoxy than the calculated amount to account for drips, uneven surfaces, and mixing waste.
• Work in a warm, dry space. Epoxy cures best at temperatures between 70°F and 85°F (21°C–29°C).
• Mix thoroughly. Stir the resin and hardener for at least 3 to 5 minutes, scraping the sides and bottom of the container.
• Level your surface. Epoxy is self-leveling, so if your surface is not flat, the resin will pool in low spots and leave thin areas on high spots.
• Use a torch or heat gun. Lightly passing a torch over freshly poured epoxy removes air bubbles and gives you a smooth, glass-like finish.

Related Construction Calculators

Working on a larger project? You may also find these tools helpful. Use the Concrete Calculator to estimate how much concrete you need for slabs, footings, or foundations. If you're finishing a floor, check out our Flooring Calculator or Tile Calculator to figure out material quantities. For countertop or surface projects that involve grout lines, our Grout Calculator can help you plan ahead. If your project involves pouring a base layer of aggregate before applying epoxy, our Gravel Calculator, Sand Calculator, or Pea Gravel Calculator can help you estimate those materials. For painting adjacent surfaces, try the Paint Calculator.

Frequently Asked Questions

How does the epoxy calculator figure out how much resin I need?

The calculator multiplies your surface dimensions by the thickness you enter to get the total volume. For flat surfaces, it uses width × length × thickness. For circular surfaces, it uses π × radius² × thickness. It then converts that volume into ounces or gallons (or milliliters and liters) so you know exactly how much epoxy resin to buy.

What is the difference between the Flat Surfaces and Circular Surfaces tabs?

The Flat Surfaces tab is for rectangular or square shapes like tabletops, countertops, and floors. You enter width, length, and thickness. The Circular Surfaces tab is for round shapes like coasters or round tables. You enter the diameter and thickness instead. The calculator uses different math formulas for each shape.

Can I mix different units like inches for width and feet for length?

Yes. Each input field has its own unit dropdown. You can set width in inches, length in feet, and thickness in centimeters if you want. The calculator converts everything automatically before doing the math.

What does the thickness field mean?

Thickness is how deep you want your epoxy layer to be. For example, if you want a thin seal coat, you might enter 1/16 of an inch. For a river table or deep pour, you might enter 1 or 2 inches. This value directly affects how much epoxy you need.

Do I have to enter a cost to use the calculator?

No. The cost field is optional. If you leave it at zero or empty, the calculator will still show you the volume and the amount of epoxy resin needed. The cost row will simply be hidden in the results.

How do I switch the results between imperial and metric?

In the results section below the calculate button, you will see two buttons labeled Imperial and Metric. Click the one you want. Imperial shows results in cubic inches, ounces, and gallons. Metric shows results in cubic centimeters, milliliters, and liters.

How accurate is the epoxy amount this calculator gives?

The calculator gives a precise mathematical result based on the dimensions you enter. However, real projects often need about 10% extra epoxy to account for uneven surfaces, mixing waste, and drips. It is a good idea to round up when you buy.

What does the volume result mean?

The volume result shows the total space your epoxy will fill, measured in cubic inches and cubic feet (imperial) or cubic centimeters and cubic meters (metric). This is the raw space calculation before it is converted into liquid measurements like ounces or gallons.

Why does the calculator show epoxy in ounces and gallons instead of weight like pounds?

Epoxy resin is sold as a liquid, so it is measured by liquid volume, not weight. Ounces here refer to fluid ounces, and gallons are liquid gallons. This matches how epoxy is packaged and priced at the store.

How do I measure the diameter for a circular surface?

Measure straight across the widest part of the circle, from one edge to the opposite edge, passing through the center. That distance is the diameter. Do not measure the radius, which is only half the distance. The calculator will divide the diameter by two on its own.

What does the Reset button do?

The Reset button sets all input fields back to their default values. Width goes back to 2 inches, length to 4 inches, thickness to 2 inches, diameter to 2 inches, and cost to $60 per gallon. This lets you start a new calculation quickly.

Can I use this calculator for epoxy floor coatings?

Yes. Use the Flat Surfaces tab and enter the width and length of your floor along with the coating thickness. Epoxy floor coatings are usually thin, around 1/16 to 1/8 of an inch, so make sure you enter the thickness in the right unit.

Does this calculator account for the resin-to-hardener mix ratio?

No. The result shows the total mixed volume of epoxy you need. Most epoxy products use a 1:1 ratio by volume, meaning you would need equal parts resin and hardener. Check your product label for the exact ratio and divide accordingly.