How much epoxy do you need? Enter your project dimensions — a rectangle, circle, or river table — and get the mixed volume in US fluid ounces and milliliters, split into resin and hardener by your product's mix ratio, with a waste buffer and an optional cost estimate.
Project shape
You need (incl. 10% waste buffer)
Total mixed epoxy
43.9 oz
≈ 1,298 ml
Resin part (1)
21.9 oz
≈ 649 ml
Hardener part (1)
21.9 oz
≈ 649 ml
Volume before buffer: 72 cubic inches = 39.9 fl oz
🕳️ Deep-pour note: every epoxy has a maximum pour depth — from 1/8" for table-top formulas to 2"+ for dedicated deep-pour resins. Exceeding it can overheat, yellow, or crack the pour. If your project is deeper than your product's limit, pour in layers and let each layer gel before the next.
📌 Conversion used: 1 cubic inch = 0.554 US fl oz = 16.39 ml. The mix ratio here is by volume — always follow your specific product's instructions.
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The volume formula
Epoxy needs are just geometry: volume = area × depth, then convert cubic inches to liquid measure. One cubic inch is 0.554 US fluid ounces (16.39 ml). For a rectangle the volume is length × width × depth; for a circle it is π × (diameter ⁄ 2)² × depth; for a river table only the river channel counts, so the calculator takes the full tabletop volume times the river's share of the surface.
Worked example: a round coaster mold, 4 inches across and 1/4 inch deep. Volume = π × 2² × 0.25 ≈ 3.14 cubic inches. Multiply by 0.554 to get ≈ 1.7 fl oz (about 51 ml) of mixed epoxy. With a 1:1 product that is roughly 0.87 oz of resin and 0.87 oz of hardener — before the ~10% waste buffer that covers mixing-cup residue and small spills.
Mix by volume — unless your product says otherwise
Mix ratios like 1:1 or 2:1 are almost always by volume. Resin and hardener have different densities, so the same product's by-weight ratio is a different number — pouring equal weights of a 1:1 by-volume epoxy puts the mix off-ratio, and off-ratio epoxy cures sticky, soft, or brittle. If you want to measure on a scale, look up the weight ratio in your product's data sheet; never guess it from the volume ratio.
Seal coat vs flood coat
On porous surfaces like wood, start with a thin seal coat — a light brushed-on layer that plugs the pores so the main pour doesn't bubble as trapped air escapes. Once it has tacked up, do the flood coat: a self-leveling pour of about 1/8 inch that forms the glassy finish. Enter 0.125 in as the depth to size a flood coat; budget roughly a third of that for the seal coat. Planning the whole build? The square footage calculator handles the surface math for odd shapes, and the paint calculator covers the finishing coats around the project.
Frequently asked questions
For a flood coat, plan on about 1/8 inch of depth over the whole surface. A 24 × 36 inch table top at 1/8" is 24 × 36 × 0.125 = 108 cubic inches ≈ 60 fl oz of mixed epoxy — add a 10% buffer and round up to about 66 oz (half a gallon kit). Seal coats beforehand use far less, roughly a third of the flood coat.
It depends entirely on the product: common ratios are 1:1 (most table-top epoxies), 2:1 (many deep-pour resins) and 3:1. The ratio is printed on the bottles and is not adjustable — mixing off-ratio leaves the pour sticky or brittle because the chemical reaction needs exact proportions. Pick your product's ratio in the calculator to see how much of each part to measure.
By volume, unless your product's instructions explicitly give a weight ratio. Resin and hardener have different densities, so a 1:1 by-volume product is usually NOT 1:1 by weight — pouring equal weights of it would be off-ratio. If you prefer a scale, check the data sheet for the weight ratio; many manufacturers list both.
Warm the resin bottles slightly (in warm water) before mixing to thin them, mix slowly to avoid whipping in air, and let the mixed epoxy sit for a couple of minutes. After pouring, pass a torch or heat gun quickly over the surface — heat pops surface bubbles. Porous wood should be sealed first with a thin seal coat, and deep projects poured in thin layers, since thick pours trap more bubbles.
It varies by product: standard table-top epoxy is limited to about 1/8–1/4 inch per pour, while dedicated deep-pour ("casting") resins allow 2 inches or more. Pouring deeper than rated causes the exothermic reaction to run away — the epoxy overheats, yellows, cracks or even smokes. For deep projects, pour in layers and let each gel before adding the next.