Loan Epoxy Estimator
Epoxy punishes guessing: too little and the pour ends mid-table, too much and you have burned the most expensive liquid in the shop. Enter the piece and the pour depth — get the mixed volume with waste allowed for, in the kit sizes stores actually sell.
The shop rule: one mixed gallon covers about 12 sq ft at ⅛ in. Deep-pour resins differ from tabletop resins — thick pours of tabletop epoxy overheat and crack; past about ¼ in per layer, use a deep-pour product and pour in lifts.
How it works
Volume is area × depth in cubic inches, divided by 231 cu in per gallon, plus your waste allowance (10% covers mixing-cup residue, drips and the lip over the edge). At ⅛ in that lands on the classic 12 sq ft per gallon rule — the estimator shows the flood-coat equivalent at exactly that rate so you can cross-check. A 1-in river pour eats a gallon every 1.6 sq ft, which is why deep pours come in multi-gallon kits. Kit counts round UP: epoxy is the one material where running short mid-pour costs the piece.
Formula & worked example
Formula: Mixed gallons = length × width × 144 × depth in inches ÷ 231 cu in per gallon, plus the waste allowance (10% standard). Flood-coat cross-check: 1 gallon covers about 12 sq ft at ⅛ in. Kits round up: 3-gal and 1-gal.
Worked example: A 6 × 3 ft top at ⅛ in with 10% waste: 18 sq ft pour = 1.54 mixed gallons — one 3-gal kit or two 1-gal kits.
When to use this
- You are coating a countertop or bar top and buying resin kits.
- You are planning a river table and the deep-pour volume is the budget.
- You want the flood-coat rule (12 sq ft per gallon) cross-checked by exact volume.
How to use it, step by step
- Measure the piece: length × width in feet.
- Pick the pour depth — 1/16 in seal, ⅛ in flood, deeper for pours.
- Leave waste at 10% unless the piece is very porous.
- Buy by the kit counts shown; round up kits, never down.
What the inputs mean
| Input | What it is | Typical values |
|---|---|---|
| Length & width | The flat pour surface | 6 × 3 ft countertop; 4 × 2 ft coffee table |
| Pour depth | Total resin thickness | 1/16 seal; ⅛ flood; 1 in river pour layers |
| Waste allowance | Cups, drips, edge loss, porous grain | 10% standard; 15–20% live edge |
Another worked example
A seal coat on a 4 × 2 ft coffee-table top: 8 sq ft × 144 × 1/16 in ÷ 231 × 1.1 waste = 0.34 mixed gallons. One 1-gallon kit seals this top and still floods it later (the flood coat at ⅛ in on the same piece takes 0.73 gal) — which is why small projects buy the gallon, not the quart.
Frequently asked questions
How much epoxy do I need for a 6 × 3 ft countertop?
At the standard ⅛-in flood depth with 10% waste: 1.54 gallons mixed — that is 1 × 3-gallon kit or 2 × 1-gallon kits. A seal coat alone on the same top takes about 0.77 gallons at 1/16 in.
How much for a river table?
Measure just the river channel, not the whole tabletop: a 6 sq ft channel at 1 in deep needs about 4.12 gallons with waste allowed. Deep pours go in lifts per the product spec — usually ¼–2 in per layer with cure time between.
Why a seal coat at all?
Raw wood outgasses as resin warms it, and those bubbles rise into your flood coat and freeze there. A thin seal coat saturates the grain and seals the air in. Skipping it is the most common cause of cloudy, bubbled finishes.
What if I mix too little mid-pour?
For tabletop epoxy you can mix a follow-up batch while the first is still wet — they bond chemically. Past the recoat window (check the product sheet) the surface needs sanding first. The kit counts here round up for exactly this reason.
How thick can one pour be?
Tabletop resins: about ⅛–¼ in per layer. Deep-pour resins: up to 2 in (some 4) per layer. Pour tabletop resin an inch deep and the exotherm can boil, crack or even smoke the piece — thickness belongs to the product, not your patience.
🐠 Filling a tank-shaped volume instead?
For cylinders, bowls and aquariums — volume in gallons and the weight of the water — the Tank Volume Estimator handles the curved shapes.
How do I measure a river table's channel?
Average the channel width at several points, multiply by length for area, and use the pour depth of the channel — then add waste at the high end, because live edges drink resin unevenly.
What temperature should the room be?
Most resins want 70–78°F for the full cure cycle, with the resin itself at room temperature before mixing. Cold resin mixes thick, traps bubbles and can cure cloudy; warm rooms shorten working time noticeably.