What this calculator does
The epoxy calculator finds the total volume of epoxy resin needed to fill a flat area to a given thickness, such as a tabletop coating or river table pour, and splits that volume into resin and hardener.
The formula
Volume is length times width times pour thickness (in cubic inches), with a waste allowance added to cover spills and surface tension loss. Since 1 US gallon equals 231 cubic inches, dividing by 231 converts to gallons. Most tabletop epoxy systems mix at a 1:1 ratio by volume, so the total is split evenly between resin (Part A) and hardener (Part B).
Always check your specific epoxy product’s mix ratio (some are 2:1 or 3:1) and adjust the resin/hardener split accordingly before mixing.
Last reviewed August 2026