How much does a gallon of epoxy weigh?

A gallon of water weighs about 8.35 lb, and most epoxies are a little denser than water, so a gallon of epoxy lands a pound or so heavier. The specific gravity printed on your product’s technical data sheet turns that into an exact figure: type it into the calculator above. Filled, pigmented or metallic products can come in heavier than the range here.

What to know about the weight of a gallon of epoxy

• A real data-sheet figure. WEST SYSTEM lists its 105 resin with 205 hardener at a cured specific gravity of 1.18, which works out to a little under 10 lb per gallon — at the heavy end of the typical range. Clear tabletop and art resins often sit lower; your own label is the only number that counts.
• The two halves of a kit don’t weigh the same. A 1-gallon 1:1 kit — TotalBoat’s TableTop, for example, is half a gallon of resin plus half a gallon of hardener — usually has a heavier resin jug, because resins tend to be denser than hardeners. That’s why a 1:1 kit is rarely 1:1 on a scale; the 1:1 epoxy by weight in grams page works through it, and 2:1 epoxy by weight does the same for deep-pour ratios.
• Almost all of it stays in the piece. Solvent-free epoxies like the WEST SYSTEM system above don’t lose weight to evaporation as they cure, so the liquid weight is close to what ends up in the table — useful when you’re sizing legs or planning how many people it takes to lift a top.
• Listing weights include packaging. A shipping weight on a store listing adds the jugs and the box, so it will read higher than the resin itself.

To go the other way — from a project’s dimensions to gallons, then pounds — start with the epoxy calculator and bring the total back here.