Epoxy Resin Calculator - Calculate How Much You Need
Epoxy resin calculator for tables, floors, and art projects. Enter length, width, and thickness to find epoxy volume in liters and gallons, plus a waste factor.
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Epoxy Calculator
An epoxy calculator finds how much epoxy resin a project needs. It works from the length, width, and thickness of the surface to be coated or filled, then adds extra material for waste. The result is shown in liters and gallons.
Epoxy resin is a liquid plastic. It is sold as two parts, a resin and a hardener, that are mixed together and left to cure into a solid, glass-like layer. People use it to coat tabletops, fill cracks in wood slabs, seal garage floors, and cast small objects such as jewelry.
How to Calculate Epoxy Resin Volume
Epoxy volume is a simple geometry problem: it is the area of the surface multiplied by how thick the epoxy layer will be.
Area (for a rectangular surface):
Volume:
Because some epoxy sticks to the mixing container, stir sticks, and tools, or soaks into a porous surface, calculators add a waste factor — a percentage of extra material:
The result in cubic centimeters is divided by 1,000 to get liters, and multiplied by 0.264172 to get US gallons.
Unit conversions used
| From | To centimeters |
|---|---|
| 1 inch | 2.54 cm |
| 1 foot | 30.48 cm |
| 1 meter | 100 cm |
| From | To square centimeters |
|---|---|
| 1 in² | 6.4516 cm² |
| 1 ft² | 929.0304 cm² |
| 1 m² | 10,000 cm² |
1,000 cm³ equals 1 liter. 1 liter equals about 0.264172 US gallons.
If the surface is not rectangular, its area can be entered directly instead of length and width. A circle's area is π × radius². An oval's area is π × (length/2) × (width/2). An irregular shape can be split into rectangles and triangles, with each area added together.
Example Calculation
A tabletop measures 100 cm by 100 cm, and the epoxy layer will be 0.5 cm thick, with a 10% waste factor.
- Area = 100 cm × 100 cm = 10,000 cm²
- Volume = 10,000 cm² × 0.5 cm = 5,000 cm³
- Convert to liters: 5,000 ÷ 1,000 = 5 liters
- Add the waste factor: 5 × 1.10 = 5.5 liters
- Convert to gallons: 5.5 × 0.264172 ≈ 1.45 gallons
The project needs about 5.5 liters (1.45 gallons) of mixed epoxy.
A second example uses imperial units: a table 6 feet long and 3 feet wide, coated 1/8 inch thick, with a 15% waste factor. Converted to centimeters, that is 182.88 cm by 91.44 cm by 0.3175 cm. The area is about 16,723 cm², the volume is about 5,309 cm³, and adding 15% waste gives about 6.11 liters, or 1.61 gallons.
Epoxy Thickness by Project Type
Typical epoxy thickness depends on the project:
| Project | Typical thickness |
|---|---|
| Tabletop flood coat | 3–6 mm (1/8"–1/4") |
| Countertop coating | 1.5–3 mm (1/16"–1/8") |
| River table (deep pour) | 1.3–5 cm (1/2"–2") |
| Resin art panel | 1.5–3 mm |
| Garage floor, per coat | 0.25–0.4 mm |
| Jewelry mold | 1–3 mm |
Most standard epoxy should not be poured thicker than about 6 mm (1/4 inch) in a single layer. A thick layer traps heat as it cures, which can cause cracking or clouding. Deeper pours, such as river tables, need a formula made specifically for deep pours, which cures more slowly and releases heat more evenly.
Waste Factor: How Much Extra to Order
The waste factor covers epoxy that never ends up on the finished surface: what sticks to the mixing cup, what drips off the edges, and what a porous surface soaks up. A common starting point is 10%, which is the default used by most calculators, including this one. Rough guide:
- 5–10%: a simple, flat pour on a sealed surface, by someone experienced with the process
- 15%: a first attempt, or a project with an unfamiliar shape
- 20% or more: raw, unsealed wood or concrete, vertical surfaces, or a pour with many embedded objects such as coins or bottle caps
Unsealed wood and concrete are porous and can absorb noticeably more epoxy than the geometry alone predicts, since the first coat partly soaks into the material rather than sitting on top of it.
Frequently Asked Questions
Why does the calculator add extra epoxy beyond the calculated volume? Some epoxy is lost to the mixing container, stir sticks, and drips, and porous surfaces absorb some of it. The waste factor accounts for this so the calculated amount is actually enough to finish the project.
Can this calculator be used for a circular or irregular shape? Yes. Calculate the area separately — for example π × radius² for a circle — and enter it using the "Enter Area Directly" option instead of length and width.
What happens if the thickness unit is wrong? Mixing up millimeters and centimeters, for instance, changes the result by a factor of 10. It is worth double-checking the thickness unit before ordering material.
How is epoxy volume converted from liters to gallons? 1 liter equals about 0.264172 US gallons, and 1 US gallon equals about 3.785 liters. The calculator shows both units at once.
Does temperature change how much epoxy is needed? Temperature changes how epoxy flows and cures, not the volume needed to fill a given space. Cold epoxy is thicker and self-levels less easily, so it can be harder to spread evenly; warming it slightly before mixing can help.
How much epoxy does a multi-layer pour need? Each layer should be calculated separately, since each has its own waste factor and the surface it sits on changes. Later layers sit on cured epoxy rather than raw wood or concrete, so they typically need less extra material than the first layer.