Epoxy resin calculator
Enter the shape and depth of your pour and see how much mixed epoxy you need, how many layers to pour it in, and which kits cover it.
Enter your project
How it is calculated
Epoxy is measured by volume, so the tool works out the volume of the space you are filling. A rectangle is length x width x depth. A round pour is pi x radius squared x depth. For odd shapes, fill the mold with water, measure it in a jug, and enter that volume (dry the mold thoroughly before pouring).
It multiplies by the number of pieces and adds your allowance for residue in cups and small spills. 231 cubic inches make one US gallon, which is 128 fl oz or 3.785 liters.
If you enter your label's maximum pour depth, the tool tells you how many layers to use. If you limit batch size (large batches heat up faster in the cup), it splits the total into equal batches. Kit suggestions use the fewest containers from common mixed sizes of 1 qt, 1/2 gal, 1 gal, 1.5 gal and 3 gal.
Worked example
A round tabletop mold 24 in across, poured 1/2 in deep, holds 3.1416 x 12 x 12 x 0.5 = 226 cubic inches. Adding 10 percent makes 249 cubic inches: 1.08 gallons (138 fl oz, 4.08 L) of mixed epoxy. With a product rated to 2 in per pour, one layer does it. Buy 1 x 1 gal kit + 1 x 1 qt kit. It weighs about 10 lb.
Epoxy gets hot as it cures. Pouring deeper than your label allows can crack, cloud or yellow the resin, and very large masses can overheat. Work with good ventilation and nitrile gloves, and follow your product's safety data sheet.
Common questions
- How do I convert cubic inches to gallons of epoxy?
- Divide by 231. One US gallon is 231 cubic inches, so a pour of 462 cubic inches needs 2 gallons of mixed epoxy. For fluid ounces, divide cubic inches by 1.805; for liters, divide by 61.02.
- How much epoxy do I need for a round table?
- Multiply 3.1416 by the radius squared by the depth. A 36 in round top coated 1/8 in thick needs about 127 cubic inches, which is 0.55 gallons before any allowance. Use the bar top epoxy calculator for thin coats with edges.
- How do I measure an odd shaped mold?
- Fill it with water, pour the water into a measuring jug, and use the custom volume option. That gives an exact answer for any shape. Dry the mold completely before pouring, because water spoils epoxy.
- Does epoxy shrink when it cures?
- Very little. Most epoxies lose only a small fraction of their volume as they cure, which the 10 percent allowance comfortably covers. A pour that looks low after curing is more often a leak or resin soaking into wood.
Related tools and guides
WoodworkingCalc results are careful estimates. Products differ, so use the coverage, mix ratio and maximum pour depth printed on your own product label, and check the numbers against your project before you mix or buy.