Epoxy resin volume calculator
Enter the size and depth of your mold, round form or river. You get the mixed epoxy to prepare, split into resin and hardener.
Result
Mixed epoxy to prepare
US fl oz
Resin (part A)
US fl oz
Hardener (part B)
US fl oz
| Net volume = length × width × depth | 159.58 US fl oz |
|---|---|
| Waste allowance = net volume × waste percentage | 15.96 US fl oz |
| Mixed epoxy to prepare = net volume + waste allowance | 175.54 US fl oz |
| Resin (A) = total × parts of A ÷ (parts of A + parts of B) | 117.03 US fl oz |
| Hardener (B) = total × parts of B ÷ (parts of A + parts of B) | 58.51 US fl oz |
How it works
The calculator works out the space the epoxy has to fill from its shape and depth, then adds your waste allowance. The total is split into resin and hardener by the mix ratio by volume printed on your product.
Formula
Rectangle: V = length × width × depth. Round: V = π × (diameter ÷ 2)² × depth. River: V = table length × average river width × depth. Total = V × (1 + waste ÷ 100). Resin = total × A ÷ (A + B) and hardener = total × B ÷ (A + B), where A : B is the mix ratio by volume. One US gallon is 231 cubic inches or 3.785 litres; one US fluid ounce is 29.57 millilitres.
Worked example
The calculator opens with this example; the result above is computed from it.
| Input | Value |
|---|---|
| Shape of the pour | Rectangle |
| Length | 24 in |
| Width | 12 in |
| Depth of the pour | 1 in |
| Waste allowance | 10 % |
| Mix ratio by volume: parts of resin (A) | 2 |
| Mix ratio by volume: parts of hardener (B) | 1 |
| Mixed epoxy to prepare | 175.54 US fl oz |
| Resin (part A) | 117.03 US fl oz |
| Hardener (part B) | 58.51 US fl oz |
A rectangular pour 24 in long, 12 in wide and 1 in deep holds 159.58 US fl oz. With 10 % waste you prepare 175.54 US fl oz: 117.03 US fl oz of resin and 58.51 US fl oz of hardener.
Common cases
| Case | Starting values | Mixed epoxy to prepare | Resin (part A) | Hardener (part B) |
|---|---|---|---|---|
| River table: six-foot slabs, six-inch river, one and a half inches thick | Length 72 in; Average river width 6 in; Depth of the pour 1.5 in; Waste allowance 10 % | 394.97 US fl oz | 263.31 US fl oz | 131.66 US fl oz |
| Round coaster mold, four inches across | Diameter 4 in; Depth of the pour 0.375 in; Waste allowance 10 % | 2.87 US fl oz | 1.91 US fl oz | 0.96 US fl oz |
| Rectangular tray mold, twelve by eight inches, one inch deep | Length 12 in; Width 8 in; Depth of the pour 1 in; Waste allowance 10 % | 58.51 US fl oz | 39.01 US fl oz | 19.50 US fl oz |
| Round table top, thirty-two inches across, two inches thick | Diameter 32 in; Depth of the pour 2 in; Waste allowance 10 % | 980.42 US fl oz | 653.61 US fl oz | 326.81 US fl oz |
Questions and answers
How much epoxy do I need for a river table?
Multiply the length of the river by its average width and by the depth of the pour, then add an allowance for waste. A river 72 in long, 6 in wide and 1.5 in deep needs 394.97 US fl oz of mixed epoxy with the allowance included: 263.31 US fl oz of resin and 131.66 US fl oz of hardener for a kit mixed 2 to 1.
How much resin does a round mold need?
The volume of a round mold is π × radius × radius × depth. A coaster mold 4 in across filled 0.375 in deep takes 2.87 US fl oz of mixed epoxy, allowance included.
Can I get the answer in litres or millilitres?
Yes. Type the measurements in inches, centimetres or millimetres and choose the unit of the result under the figures. A tray mold 12 in by 8 in and 1 in deep, is 58.51 US fl oz; switch the unit and the page converts it for you.
Assumptions and limits
- Use inside measurements of the mold. Anything that sits in the epoxy, such as wood offcuts or embedded objects, is not subtracted.
- A river is treated as a straight channel with the average width you enter. Live edges are irregular, so measure the gap in several places.
- The waste allowance is a share of the net volume. Epoxy that soaks into unsealed wood or leaks from the form is not estimated separately.
- The resin and hardener split uses the ratio by volume. A ratio by weight gives different amounts; the mix ratio calculator converts between the two.
- The mold is assumed to have straight sides and a flat bottom, filled to the depth you enter.
The result is an estimate for planning, not professional advice.
Sources
- Wikipedia: Cylinder (volume of a circular cylinder with radius r and height h: V = pi r^2 h)retrieved 2026-10-12
- TotalBoat epoxy calculator page: rectangular volume = length x width x coating thickness; round = radius squared x pi x thickness; add 5-10 % for wasteretrieved 2026-10-12
- Omni Calculator, epoxy calculator: Volume = length x width x height; Volume = pi x radius^2 x height; two worked examplesretrieved 2026-10-12
- MiniWebtool epoxy resin calculator: V_total = V x (1 + waste / 100); resin = V_total x resin parts / total partsretrieved 2026-10-12
- Wikipedia: Gallon (the US gallon is legally defined as exactly 231 cubic inches, i.e. 3.785411784 litres; 128 US fluid ounces)retrieved 2026-10-12
Last updated:
Method in depth: Epoxy volume formula: how much resin a pour or a coat needs
Cite this page: Resin Math, “Epoxy resin volume calculator”, https://resin-math.pages.dev/epoxy-pour/epoxy-resin-volume-calculator/ (updated 12 October 2026).
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