Mix
Sizes are in inches (or cm), thickness in inches (or mm): type 1/8, 0.125 or 1 1/2. Add one pour for each layer or piece. Everything is saved on this device.
About the epoxy resin calculator
This free epoxy resin calculator tells you how much epoxy to mix. Enter the size of your table top, coating, mold or the gap of a river table, and the thickness of the pour. You get the volume in fluid ounces, gallons or litres, split into resin (part A) and hardener (part B) by the mix ratio on your kit.
It adds a little extra for the drips over the edges and for what stays in the mixing cup, and shows the weight and the cost too.
Features
- Three shapes — rectangle (table top, bar top, coating, mold), circle (round table, coaster) and river table
- Several pours — add a seal coat and a flood coat, or a set of coasters, in one list
- Mix ratio — 1 : 1, 2 : 1 or 3 : 1 by volume, split into resin and hardener
- Extra for waste — 0–20% for drips, edges and the cup
- Ounces, gallons, litres — fl oz for small pours, gallons for big ones, and both units
- Weight and cost — weight at the density on your label, and a price per gallon or litre
- Deep-pour warning — a note when a layer is thicker than 1/4 in (6 mm)
- Saved on this device — your list is still there when you shop
How the volume is worked out
Epoxy is a liquid, so you need its volume: area × thickness.
- Rectangle: length × width × thickness. A 48 × 24 in table top with a 1/8 in coat: 48 × 24 × 0.125 = 144 cubic inches.
- Circle: 3.1416 × diameter × diameter ÷ 4 × thickness.
- River table: length × average river width × depth. Measure the river in a few places and take the average.
Then the calculator turns cubic inches into fluid ounces (1 fl oz = 1.805 cubic inches; 1 US gallon = 231 cubic inches) and adds the extra. 144 cubic inches is 2.36 litres, and with 10% extra 87.8 fl oz (0.69 gal). At 1 : 1 that is 43.9 fl oz of resin and 43.9 fl oz of hardener.
Mix ratio: resin and hardener
The ratio is on the kit label. The calculator splits the total like this:
| Ratio (by volume) | Resin (A) | Hardener (B) | 1 gallon of mix |
|---|---|---|---|
| 1 : 1 | 1/2 | 1/2 | 64 fl oz + 64 fl oz |
| 2 : 1 | 2/3 | 1/3 | 85.3 fl oz + 42.7 fl oz |
| 3 : 1 | 3/4 | 1/4 | 96 fl oz + 32 fl oz |
Some kits give the ratio by weight, not by volume. Resin and hardener have different densities, so a weight ratio does not work with measuring cups. Use a scale for those kits, and follow the label.
Worked examples
These numbers come from the calculator with 10% extra:
| Project | Size | To fill | Mixed epoxy to buy |
|---|---|---|---|
| Table top coat | 48 × 24 in, 1/8 in | 144 cu in | 87.8 fl oz (0.69 gal) |
| Round table | 36 in across, 1/8 in | 127 cu in | 77.6 fl oz (0.61 gal) |
| Thin seal coat | 60 × 30 in, 1/16 in | 113 cu in | 68.6 fl oz (0.54 gal) |
| 6 coasters | 4 in across, 1/4 in | 19 cu in | 11.5 fl oz |
| River table, 2 : 1 | 72 in long, 6 in wide, 1.5 in deep | 648 cu in | 3.09 gal — 2.06 gal resin + 1.03 gal hardener |
In metric: a 120 × 60 cm table top with a 3 mm coat is 2,160 cm³, so 2.38 litres with 10% extra (1.19 L of each part at 1 : 1). A river 180 cm long, 15 cm wide and 4 cm deep is 10.8 litres, so 11.88 litres — 7.92 L of resin and 3.96 L of hardener at 2 : 1.
How far does epoxy go?
One gallon (231 cubic inches) or one litre of mixed epoxy covers:
| Thickness | One gallon covers | Thickness | One litre covers |
|---|---|---|---|
| 1/16 in | 25.7 sq ft | 1 mm | 1 m² |
| 1/8 in | 12.8 sq ft | 2 mm | 0.5 m² |
| 1/4 in | 6.4 sq ft | 3 mm | 0.33 m² |
| 1/2 in | 3.2 sq ft | 5 mm | 0.2 m² |
These are without the extra. Real pours always lose some epoxy over the edges and in the cup.
Thick pours
Epoxy gets warm as it cures. In a thick layer the heat cannot get out, so the resin can crack, yellow or even smoke. Table-top (coating) epoxy is usually poured about 1/8 in (3 mm) at a time. For a river table or a deep mold, use a deep-pour (casting) resin, or pour several thin layers and let each one cool. The label gives the most depth per layer — follow it.
Frequently asked questions
How much epoxy do I need for a table top?
Multiply length × width × thickness, then turn it into ounces. A 48 × 24 in table with a 1/8 in coat is 144 cubic inches, or about 80 fl oz. With 10% extra for the edges, mix about 88 fl oz (0.69 gallon).
How thick should an epoxy coat be?
A seal coat is very thin (about 1/16 in or less) and fills the pores of the wood. A flood coat is usually about 1/8 in (3 mm). Many projects use one seal coat and one or two flood coats — add each one as its own pour.
How much epoxy for a river table?
Measure the length of the river, its average width and its depth. 72 × 6 × 1.5 in is 648 cubic inches, about 2.8 gallons, or 3.1 gallons with 10% extra.
How much extra epoxy should I mix?
About 10% for a coating that runs over the edges, and 5% for a closed mold. Mix in small batches if you are not sure: epoxy that has set in the cup is lost.
Why does my kit not match the number?
Kits are sold by the total of both parts, in sizes like 1 quart, 1 gallon or 2 gallons. Buy the next kit size up from the "mixed epoxy" line.
Is the weight exact?
No. Most epoxies weigh about 1.05–1.15 g/ml (9 lb per gallon). Type the figure from your label under Density for a closer number.
Related tools
- Unit Converter — fluid ounces, gallons, litres and ml
- Gallons to Liters — kit sizes in litres
- ml to oz — small pours for molds and coasters
- Concrete Calculator — volume of a slab or a post hole
- Ratio Calculator — other mix ratios
How to use it
- Choose Feet & inches or Metres & cm
- Pick the shape of the first pour and enter its size and thickness (or depth)
- Use Add another pour for a second coat, more pieces or another mold
- Pick the mix ratio from your kit and the extra for drips
- Add a price per gallon or litre if you want the cost
- Read the mixed epoxy, the resin and the hardener, then press Copy the list
