Epoxy Resin Calculator
Volume for a coating, a river table or a mould — and how many pours it has to be split into.
Epoxy to mix
1.13 gal
- Volume
- 216.0 in³
- With waste
- 261.4 in³
- Also
- 144.8 fl oz · 4.28 L · about 10.4 lb
- Pours needed
- 1 — within the depth limit
- Kits to buy
- 2
- Purchased
- 2.00 gal
- Leftover
- 0.87 gal
- Coverage at 0.1250 in
- 12.8 sq ft per gal
Mix the full quantity in one batch where you can — colour and clarity vary slightly between mixes.
Buying the slab for it? Use the board foot calculator →
How this is calculated
coating in³ = area(sq ft) × 144 × thickness(in) river in³ = length × width × depth (all inches) round in³ = π × (diameter/2)² × depth mix = in³ × (1 + edge loss) × (1 + waste%) gallons = mix / 231 layers = ceil( depth / max depth per pour )
Everything here is one calculation in different clothes: volume in cubic inches, divided by 231 for US gallons, 1.8047 for fluid ounces or 61.02 for litres. Kits are described by total mixed volume, so a one gallon kit yields a gallon once both parts are combined — you do not buy a gallon of each.
The layer count is the part worth taking seriously. Epoxy cures by an exothermic reaction, and a deep mass holds its own heat instead of shedding it. Past the product depth limit the pour cooks itself: yellowing, cracks, sometimes smoke. Splitting it into layers within the limit, each fully cured before the next, is the only fix — thinning the resin makes it worse, not better.
Coating coverage per gallon
| Thickness | Sq ft per gallon | Gallons per 10 sq ft | Fl oz per sq ft |
|---|---|---|---|
| 0.0313 in | 51.3 | 0.19 | 2.49 |
| 0.0625 in | 25.7 | 0.39 | 4.99 |
| 0.0938 in | 17.1 | 0.58 | 7.48 |
| 0.1250 in | 12.8 | 0.78 | 9.97 |
| 0.1875 in | 8.6 | 1.17 | 14.96 |
| 0.2500 in | 6.4 | 1.56 | 19.95 |
| 0.5000 in | 3.2 | 3.12 | 39.90 |
Bare volume, before waste or edge run-off. A table top finished at 1/8 inch is usually reached in two or three flood coats rather than one, and a seal coat over porous wood goes on first and is not counted in the finished thickness at all.
Common pours
| Project | Volume | Gallons | Litres | With 10% waste |
|---|---|---|---|---|
| 60" × 8" × 2" river | 960 in³ | 4.16 | 15.73 | 4.57 gal |
| 72" × 6" × 1.5" river | 648 in³ | 2.81 | 10.62 | 3.09 gal |
| 36" × 24" bar top at 1/8" | 108 in³ | 0.47 | 1.77 | 0.51 gal |
| 8 ft × 30" table at 1/8" | 360 in³ | 1.56 | 5.90 | 1.71 gal |
| 12" round mould, 2" deep | 226 in³ | 0.98 | 3.71 | 1.08 gal |
| 4" × 4" × 6" casting block | 96 in³ | 0.42 | 1.57 | 0.46 gal |
Generated by the same conversions the tool uses. Note how quickly a river table gets expensive: doubling the depth doubles the resin, and resin is nearly always the largest line on the bill.
Frequently asked questions
How much epoxy do I need per square foot?
One US gallon covers about 25.7 square feet at 1/16 inch and about 12.8 square feet at 1/8 inch, since a gallon is 231 cubic inches spread over 144 square inches per square foot. Most table top coatings are poured at 1/8 inch total across two or three flood coats. Work in volume rather than area whenever the piece is not a flat rectangle — a river table or a mould is a volume problem, and area shortcuts miss badly.
How deep can you pour epoxy in one layer?
It depends entirely on the product, and it is the one specification you cannot ignore. Table top resin is formulated for 1/8 inch flood coats and will overheat past about a quarter inch. Deep pour resin is formulated to cure slowly and handles two inches, sometimes four. Pouring a fast resin deep does not give you a thick pour, it gives you a hot mass that yellows, cracks or smokes.
How much resin for a river table?
Measure the void, not the table: length by average width of the gap by depth, in inches, then divide by 231 for gallons. A 60 by 8 by 2 inch river is 960 cubic inches, about 4.2 gallons before waste. Live edges make the gap wider at some points than others, so measure at several places and average, then add 10 to 15% — an under-poured river cannot be topped up invisibly once it has cured.
Do I count resin and hardener separately?
No. Kits are sold and described by the total mixed volume, so a one gallon kit yields one gallon of mixed epoxy from its two parts. What matters is mixing them at the ratio the manufacturer specifies, by weight or by volume as stated, and mixing thoroughly including the sides and bottom of the cup. Off-ratio epoxy does not cure soft, it stays tacky permanently.
How much extra should I mix?
About 10% for a mould or a river, and more for a coating with free edges, because a flood coat runs off every unrestrained side and that loss is real. Some material also stays behind in the mixing cup and on the spreader. Running out mid-pour is far worse than mixing too much: the seam between a cured layer and a fresh one shows, and on a self-levelling coat you cannot blend it away.
Does temperature change how much I need?
Not the volume, but it changes everything else. Cold epoxy is thick, traps bubbles and cures slowly or not at all below the product minimum, usually around 70°F. Warm epoxy flows thinner and cures faster, which shortens your working time and can push a deep pour into an exotherm. Bring the resin and the workspace to the recommended temperature and hold it there through the cure, not just at the pour.
Results are planning estimates. Always follow your own product data sheet for mix ratio, maximum pour depth, temperature range and cure time — these vary widely between brands, and the depth limit in particular is a safety specification, not a suggestion. Mix in a ventilated space and wear gloves.