Epoxy Resin Calculator
Work out how much epoxy resin to mix for a river table, tabletop coat, coasters or a mold, including Part A and Part B.
How to use this epoxy calculator
Measure the space the resin will fill in inches: the river channel in a river table, the top of a table you're coating, or the inside of a mold. Enter how deep the pour is and how many identical pieces you're making. The mix ratio and the maximum pour depth are on your resin's label.
- Tabletop or coating epoxy: usually 1:1, poured about ⅛ inch (0.125) at a time.
- Deep-pour or casting epoxy: often 2:1 or 3:1, poured 1 to 2 inches at a time or more.
Pouring deeper than the label allows can make the resin overheat, crack, yellow or even smoke, so the calculator tells you how many layers to split the pour into.
The math behind it
- Volume = length × width × depth (or 3.1416 × radius² × depth for circles) × pieces, plus extra.
- Fluid ounces = cubic inches ÷ 1.805. Gallons = cubic inches ÷ 231. Milliliters = cubic inches × 16.39.
- Part A = total × ratio ÷ (ratio + 1), and Part B is the rest.
- Pours = depth ÷ max pour depth, rounded up.
Example: a river 48 inches long, 6 inches wide and 1.5 inches deep is 432 cubic inches. With 10% extra that's about 263 fl oz (2.06 gallons). At 2:1 that's about 176 fl oz of Part A and 88 fl oz of Part B, in one 1.5-inch pour.
Often used together
Quick answers
How much epoxy do I need for coasters?
A 4-inch round coaster ¼ inch deep holds about 3.1 cubic inches, or 1.7 fl oz of mixed resin. A set of 4 needs about 7 fl oz, plus a little extra.
Should I measure epoxy by volume or by weight?
Use whatever your resin's instructions say. Many list both, and the two ratios are different for the same product because Part A and Part B weigh different amounts. This calculator uses volume.
Why did my epoxy crack or turn yellow?
Usually the pour was too deep for that resin, so it got too hot while curing. Split deep pours into layers, waiting until each one is firm before pouring the next.