Measurement unit
Channel width at evenly spaced points

Measure the gap between the two wood edges at evenly spaced points from one end to the other. Use 2 to 5 points and leave unused boxes empty.

Take this from your resin's data sheet. It sets how many layers you need.

Optional. Use 0 if the channel is clear.

Most epoxy resins are 1.05–1.15 g/ml. Check your data sheet.

Covers resin left on cups and stir sticks. Use 0 for the exact volume.

River table resin

Average channel width11.5 cm
Exact channel volume6,900 ml
Resin to mix7,590 ml
Litres7.59 L
US fluid ounces256.65 fl oz
Number of layers1
Resin per layer7,590 ml
Depth per layer50 mm
Weight8,349 g

Calculator results are planning estimates. Check your resin maker's instructions, mixing ratio, and product limits before pouring.

Measuring an uneven river channel

A river channel may change width along the slab. Measure the gap between the wood edges at evenly spaced points from one end to the other. The calculator estimates average width from these readings, then multiplies by length and depth.

For example, widths of 8 cm, 14 cm, and 10 cm at three equally spaced points give an average width of 11.5 cm: ((8 + 14) / 2 + (14 + 10) / 2) / 2 = 11.5 cm. The result is still an estimate because real edges may curve between the points.

Subtract the volume occupied by objects inside the channel if you have a reliable estimate. Check the chosen resin's maximum pour depth and layer timing separately.

River Table Calculator

Estimate resin for the channel between two slabs of wood by measuring the channel length, depth, and width at several points. The tool uses the width readings to estimate an average rather than assuming the channel has one width from end to end.

How to use the river table calculator

  1. Measure the channel length and planned fill depth.
  2. Record the gap width at evenly spaced points along the channel.
  3. Enter the measurements in one unit system.
  4. Enter the allowed layer depth from your resin's data sheet.
  5. Review the estimated channel volume, allowance, layer count, and weight.

Why several width readings matter

A channel that narrows or widens cannot be measured well with one width reading. Add more readings where the wood edges change direction. The estimate may still vary if the edge curves between measurement points or the channel is not level.

Subtract space occupied by objects or wood that will sit inside the channel when you can measure that displacement reliably. Confirm the permitted pour depth and curing instructions for the product separately.