Measure a simple river with one average width or switch to Irregular river and enter multiple live-edge gap measurements. EpoxyCalc calculates the resin volume, adds your chosen waste allowance and then matches the project against verified deep-pour product data and kit sizes.
Calculate quantity first. Product matching only uses verified manufacturer data.
Use irregular mode when the live-edge gap changes noticeably along the table.
Best Match uses technical fit first. Best Value and Lowest Waste are awarded only when the full current kit-price set has been verified.
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A river table is different from a solid rectangular casting because only the gap between the slabs is filled with resin. For a simple river, the basic calculation is river length × average epoxy width × pour depth. The result is the raw geometric volume before any extra resin is added for practical losses.
If the live edges change width along the table, one average measurement can overestimate or underestimate the real cavity. EpoxyCalc's irregular mode uses several width measurements and treats the space between each pair as a trapezoidal segment. Those segments are summed before the pour depth and waste allowance are applied.
Measure the full river length first. Then take gap measurements at evenly spaced positions from one end to the other. Five measurements are a useful starting point for a moderately irregular river; use more points where the live edge narrows, widens or changes direction sharply.
Keep all measurements at the same reference level and use the actual resin gap, not the full tabletop width. The calculator assumes one constant pour depth. Large voids, cracks, knot holes, end dams and other cavities should be measured separately if they will also be filled with epoxy.
Suppose the resin river is 72 inches long, averages 6 inches wide and is 2 inches deep. The raw cavity is 864 cubic inches, which is about 3.74 US gallons (14.2 litres). With a 10% planning allowance, the purchase target becomes about 4.11 gallons (15.6 litres).
An irregular river with the same length can require noticeably more or less resin depending on the live-edge shape. That is why multiple width measurements are useful when the gap varies substantially.
Resin quantity alone does not tell you which epoxy is suitable. A product also needs to be approved by its manufacturer for the project type, layer thickness and application conditions. Two products sold as deep-pour resin can have different maximum layer limits.
After calculating your quantity, EpoxyCalc can compare the project with verified product data and estimate how many pours or kit sizes may be needed. See the deep pour epoxy comparison for a side-by-side overview, or browse the verified epoxy product database.
Practical losses vary by project. Mixing containers retain material, live edges can contain small voids, molds may not be perfectly square and measurements are rarely exact. Instead of hiding a fixed safety factor inside the formula, the calculator keeps your waste allowance separate so you can see the raw volume and the planned purchase quantity.
Seal coats, crack filling and major void filling can consume additional resin beyond the main river calculation. Estimate those separately when they are significant.
Multiply river length × average epoxy width × pour depth for a simple river. For a changing live edge, use multiple width measurements so the shape is represented more accurately, then add the waste allowance you want for the purchase plan.
Measure the gap at evenly spaced points along the full river length. Add extra measurement points wherever the live edge changes sharply. The irregular calculator uses neighboring measurements to estimate each section of the river.
Thick castings generally require a resin specifically approved for deep pours. Always compare your intended layer depth with the current manufacturer guidance for the exact product and temperature.
No, unless the entire tabletop is being cast from resin. For a normal wood-and-resin river table, measure only the gap that will actually be filled with epoxy.
Need a simple rectangular casting instead? Use the deep pour epoxy calculator. For details on how product limits and sources are handled, see the EpoxyCalc methodology.