Deep Pour Epoxy Calculator

Calculate epoxy volume for river tables, bar tops, and deep casts — rectangle, round, or river shapes — with pour lifts, wait times, and A:B mix ratio.

Calculate Epoxy Volume for Your Mold

Enter your mold's length and width (or diameter for round, or the two slab widths for a river table) plus your total pour depth. The calculator returns the epoxy volume in gallons — with a standard 10% overage built in — plus a to-scale shape preview. For pour lifts, mix ratio, and cure guidance, see the FAQs below.

Mold Shape
Deeper than about 2 in? Split it into multiple pours — see the FAQs below for lift depth and wait times.

Enter your mold dimensions and pour depth to calculate.

Deep pour epoxy cures via an exothermic reaction — pours deeper than about 2 in typically need to go in multiple lifts with a 24–36 hr wait between each (see the FAQs below). This total includes a standard 10% overage allowance. Volumes here are estimates only; always confirm max pour depth, mix ratio, and cure schedule against your product's Technical Data Sheet (TDS). Trade Epoxy is not responsible for miscalculations, material shortfalls, or job outcomes arising from use of this calculator — see our full Disclaimer for details.

How the Deep Pour Epoxy Calculator Works

  1. Choose your mold shape — rectangle, round, or river table
  2. Enter the length and width (or diameter for a round mold)
  3. For a river table, enter both slab widths — the calculator subtracts them from the table width to estimate the river gap
  4. Enter your total desired pour depth
  5. Read the total gallons to order, and check the shape preview against your mold

Examples

ScenarioBar top — 72 × 24 in, 1.5 in deepInputRectangle · 72 in × 24 in · 1.5 in deepResult12.34 gal to order (includes 10% waste)
ScenarioLive-edge river table — 84 × 36 in table, 15 in + 14 in slabsInputRiver · 84 in long · 7 in river gap · 1.25 in deepResult3.50 gal to order (includes 10% waste)
ScenarioDeep cast block — 12 × 12 in, 4 in total depthInputRectangle · 12 in × 12 in · 4 in deepResult2.74 gal to order (includes 10% waste) — pour in 2 lifts of 2 in, waiting 24–36 hrs between

Frequently Asked Questions

What's the difference between deep pour and bar top epoxy?

Bar top epoxy is formulated for thin coats — 1/8" to 1/4" — and reacts fast, generating too much heat to pour thick. Deep pour epoxy uses a slower-reacting chemistry with a longer working time, so it can be poured 1" to 4" thick in a single lift (deeper with multiple lifts) without overheating, cracking, or clouding.

How deep can I pour epoxy in a single lift?

Most deep pour epoxies are rated for up to 2 in per pour; some high-build formulations allow up to 4 in. Always check the product's Technical Data Sheet (TDS) — pouring deeper than rated risks a dangerous exothermic reaction that can crack, cloud, or even scorch the resin. For anything deeper than the rating, split the pour into multiple lifts.

How do I measure a river table's pour width?

Subtracting each slab's width from the total table width (what this calculator does) gives a fast estimate for straight-edged slabs. If the river curves, tapers, or has an irregular live edge, measure the actual gap at 3–4 points along its length and use the average instead.

Why do I need to wait between pour lifts?

Each lift needs to firm up — while staying slightly tacky — before the next one goes on, typically 24 to 36 hours, so the layers chemically bond into one seamless block. Pouring the next lift too soon can trap heat and vapor from the layer below, or blend the two pours unevenly.

What waste allowance should I use?

This calculator automatically builds in a standard 10% overage for routine mixing residue, dam or mold seepage, and container waste. Order an extra 10–15% on top of that for irregular molds, rough or porous substrates, or the first time you're pouring a new product and don't yet know how it behaves.

Do I need to account for embedded objects?

Yes — anything embedded in the pour (coins, rocks, a phone, LED strips, bottle caps) displaces resin and takes up volume the epoxy would otherwise fill. Estimate the object's volume and subtract it from the total this calculator returns so you don't over-order.

Important Notes

  • Volume is calculated as footprint area × depth ÷ 231 cubic inches per gallon — the standard conversion for any straight-walled or round mold
  • Seal porous wood and other absorbent substrates with a thin seal coat before the deep pour — unsealed wood off-gasses and creates bubbles that migrate up through hours of curing epoxy
  • Never exceed your product's rated single-lift depth — deep pour epoxy cures via an exothermic reaction, and too much mass in one pour traps heat that can crack, yellow, or cloud the casting
  • For irregular or curved river gaps, measure the actual width at several points and use the average instead of the straight slab-width subtraction
  • Full cure (hard enough for finishing and light use) typically takes 3–7 days after the final lift, even though each lift may feel tack-free within 24–36 hours
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Deep Pour vs. Bar Top: Picking the Right Epoxy for the Job

The two products aren't interchangeable. Bar top epoxy is built to self-level a thin, glass-like coat in one pass — pour it more than about 1/4" thick and its fast reaction can overheat, yellow, or crack. Deep pour epoxy trades that speed for a much longer working time and lower peak exotherm, so it can fill a mold 1"–4" deep without the same risk. For anything deeper still — a thick river table or a casting block — the move is staged "lifts": pour up to your product's rated depth, let it firm up for 24–36 hours, then pour the next lift directly on top. The layers chemically bond into one seamless piece, no sanding required between pours. Whichever product you're using, the volume math is the same length × width (or footprint) × depth ÷ 231 this calculator runs — the only thing that changes is how many lifts you split it into.