An epoxy resin calculator takes the guesswork out of buying supplies by computing the exact volume of resin and hardener you need for your project. Whether you are sealing a tabletop, casting a mold, or filling the void in a river table, entering your dimensions and mix ratio gives you precise quantities in fluid ounces and milliliters — so you order the right number of kits the first time.
Epoxy Resin Estimator
Project Type
Surface Dimensions
Options
Detailed Breakdown
Kits Needed
Choose the kit size that minimizes leftover epoxy. One large kit is usually more economical than several small ones.
How to Use the Epoxy Resin Calculator
Buying too little epoxy mid-project is a serious problem — you cannot easily match the cure state of a previous batch, and most projects require a continuous pour. Buying too much is wasteful and expensive. This epoxy resin calculator takes your dimensions, mix ratio, and a small waste buffer to give you precise quantities of resin and hardener in both fluid ounces and milliliters, so you order exactly the right number of kits before you start.
Step 1: Select Your Project Type
Choose from three project types at the top of the calculator. Coating is for thin flood coats on tabletops, bar tops, countertops, and artwork — typically 1/8 inch (3 mm) or less. Casting is for filling molds: river stones, coasters, paperweights, or decorative objects. River Table calculates the epoxy needed to fill the natural void between two live-edge wood slabs, with an adjustable void coverage percentage to account for the wood that narrows the channel.
Step 2: Enter Your Dimensions
Use the unit toggle to work in imperial inches and feet or metric centimeters and meters. For coating and river table projects, enter the surface length, width, and pour depth. For castings, enter the mold length, width, and height. The calculator converts all dimensions to a single cubic-inch or cubic-centimeter volume before converting to fluid ounces or milliliters. For river tables, the void coverage slider (default 80%) accounts for the portion of the channel actually filled by epoxy — if your void is unusually narrow or wide, adjust accordingly.
Step 3: Set Your Mix Ratio
The mix ratio (resin to hardener) is determined by your specific epoxy product — always check the manufacturer's instructions. The most common ratios are 1:1 (equal parts, typical for coating epoxies) and 2:1 (two parts resin to one part hardener, common in casting and deep-pour products). The calculator splits the total volume according to your chosen ratio and tells you exactly how many fluid ounces and milliliters of each component to measure out.
Step 4: Add a Waste Percentage
The default 5% waste factor is suitable for most projects. It covers epoxy that clings to mixing containers and stir sticks, small overflows at the edges, and material that soaks into porous wood before sealing. For large river tables or highly porous substrates, increase to 10–15%. For precision mold castings with smooth walls, you may reduce it to 2–3%.
Step 5: Choose Your Kit Size
The results panel shows how many 16 oz, 32 oz, and 1-gallon kits you would need to cover the total volume. Buy the fewest kits that cover your requirement — larger kits are almost always more economical per ounce. If your project calls for, say, 45 fl oz total, one 32 oz kit and one 16 oz kit (48 oz combined) is the most efficient combination. The resin and hardener breakdown tells you how much of each component you will actually use from those kits.
Frequently Asked Questions
Is this epoxy resin calculator free to use?
Yes, this epoxy resin calculator is completely free with no signup required, no paywalls, and no limits on calculations. All math runs entirely in your browser — your project dimensions are never sent to any server and remain fully private on your device.
Is my project data private when I use this tool?
Absolutely. Every calculation runs locally in your browser using client-side JavaScript. No project dimensions, mix ratios, or any other information are ever transmitted to a server. Your data stays entirely on your device.
What is the difference between a 1:1 and 2:1 mix ratio?
The mix ratio refers to the proportion of resin to hardener by volume. A 1:1 ratio means equal parts resin and hardener — for every 100 ml of total epoxy, you use 50 ml resin and 50 ml hardener. A 2:1 ratio means two parts resin to one part hardener — for every 300 ml total, you use 200 ml resin and 100 ml hardener. Always use the exact ratio specified by your epoxy manufacturer, as incorrect ratios will result in uncured or brittle resin.
How deep should an epoxy coating pour be?
For table-top coatings and bar tops, standard flood coats are typically 1/8 inch (3 mm) thick. For river tables and deep pours, most deep-pour epoxies allow up to 2 inches (50 mm) per pour. Standard casting epoxies should be poured no more than 1/4 to 1/2 inch (6–12 mm) at a time due to heat buildup from the exothermic curing reaction. Always check your specific product's maximum pour depth.
Why should I add a waste percentage to my epoxy calculation?
A waste factor of 5–10% accounts for epoxy that sticks to mixing containers and stir sticks, material lost while spreading, overflow when applying flood coats to a surface, and any resin that drips off edges. Buying slightly more than your calculated amount prevents costly mid-project shortages, since mixing a new batch of epoxy to exactly match the previous pour's cure state is very difficult.
How do I choose the right epoxy kit size?
Common epoxy kit sizes are 16 oz, 32 oz, and 1 gallon (128 oz). The calculator shows how many of each kit size you would need to cover your total volume. Choose the kit size that minimizes leftover epoxy — it is usually cheaper to buy one larger kit than multiple small ones. Some projects may require a mix of kit sizes for the most economical purchase.
What is the difference between coating, casting, and river table epoxy?
Coating epoxy is designed for thin surface applications (1/8 inch or less) on tabletops, countertops, and artwork. It has a low viscosity for self-leveling. Casting epoxy is formulated for thick pours into molds, generating less heat per inch. River table epoxy is a deep-pour casting formula optimized for the thick void fills in live-edge wood projects, often allowing pours of 1–2 inches in a single pass. Each type has different pour depths, cure times, and mix ratios.
Can I use this calculator for metric measurements?
Yes. The calculator accepts dimensions in either imperial (inches and feet) or metric (centimeters and meters) units. Results are displayed in both fluid ounces and milliliters so you can shop for epoxy products regardless of which unit system your supplier uses. Simply enter your dimensions in the unit system you prefer.