Free epoxy calculators for every resin project

Start with the one named after your project — river table, tabletop, countertop, garage floor, resin art, molds — because each handles its own quirks (river widths that wander, drips off a table edge, floor kits sold by coverage). For any other rectangle or circle, the epoxy resin calculator does the plain length × width × depth math.

About 12.8 sq ft at a 1/8 in flood coat, and about 25.7 sq ft at 1/16 in. Floor coatings go on much thinner: at 10 mils (thousandths of an inch) a gallon of 100%-solids epoxy covers about 160 sq ft. The epoxy coverage chart lists every common thickness in US and metric units.

Measure only the river channel: length × average width × depth. A 6 ft river averaging 8 in wide and 1.5 in deep, poured 1/16 in proud of the wood for flattening, is about 3.9 gallons, or about 4.3 gallons with a 10% allowance. The 6 ft river table example walks through it; use the river table calculator for your own slabs.

Deep-pour epoxy is for thick pours like river tables and castings; tabletop epoxy is for thin coats around 1/8 in. Pouring a tabletop epoxy too thick can make it overheat. See deep pour vs tabletop epoxy.

Whichever your label gives — and don’t mix the two up, because resin and hardener rarely weigh the same per cup. Weighing on a digital scale is more accurate for small batches. The mix ratio calculator converts a volume ratio to grams or ounces.

Longer than the label says — as a rule of thumb, roughly twice as long for every 18°F (10°C) below the temperature the label times are given for. Below the label’s minimum, some epoxies don’t cure fully at all. The cure time calculator adjusts the label figures for your temperature, and how long epoxy takes to cure explains dry vs full cure.

They are planning estimates. Wood absorbs some resin, forms leak, and every product has its own coverage, density and depth limits. Check the label and technical data sheet, and buy a little extra.