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Epoxy Resin Calculator
How much resin to mix for a river table, countertop, coating or mould.
Part of the 🏠 Homeowners and DIYers toolkit, with more tools made for the job.
Measure only the part you pour into, such as the river channel.
For an uneven channel, average the narrowest and widest.
Resin sticks to cups and spills. Leave empty for 10%.
On the product data sheet. Deeper pours need layers.
From the product. For a 2 to 1 mix, type 2 here.
and 1 here.
Type the size of the pour and its depth, and the resin you need to mix appears here.
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Enter the length, width and depth of the part you are filling. This shows the litres of resin to mix, with an allowance for waste, the layers a deep pour needs and the resin and hardener amounts.
Resin is expensive and you cannot easily top it up once it has cured, so working out the volume first is worth doing. The sum is length times width times depth. The two things that catch people out are measuring the wrong area (for a river table, only the channel you are pouring into, not the whole slab) and the depth limit of the resin. Table-top epoxy is meant for thin coats, and deep-pour resin is made for thick layers. Going past the limit risks overheating, so you pour in layers.
How it’s worked out
- Volume is length times width times depth, with centimetres and millimetres or inches converted to litres or gallons.
- A waste allowance is added for resin that sticks to cups and spills. The tool uses 10 percent unless you change it.
- Layers are the depth divided by the most your resin can pour at once, rounded up. Each layer cures before the next.
- If you give a mix ratio by volume, such as 2 to 1, the total is split into resin and hardener.
A 200 cm by 8 cm channel poured 50 mm deep is 8 litres. With 10 percent extra you mix 8.8 litres. If your resin pours 20 mm at a time, that is 3 layers, and at a 2 to 1 mix it is about 5.9 litres of resin and 2.9 of hardener.
Common mistakes
- Measuring the whole slab. Only the part you pour into counts, so measure the channel or the mould.
- Pouring too deep for the product. Check the data sheet for the maximum depth per layer.
- Ignoring the mix ratio. Resins are mixed by volume or by weight, and the wrong ratio can leave a sticky or soft finish.
- Forgetting the waste. Cups, spills and what you cannot scrape out add up, so mix a little extra.
Questions
Is this volume or weight?
Volume. Resin density differs by product, so check the data sheet if you buy by weight. It is usually close to that of water.
How do I measure an uneven river?
Take the narrowest and widest points and average them, then multiply by the length and depth. For a very irregular channel, a rough sum is better than none.
What is deep-pour epoxy?
A resin made to be poured in thick layers, often a few centimetres, with slower curing so it does not overheat. Table-top resin is meant for thin coats. Check what yours allows.
Do I need to seal the wood first?
Often yes, because air from the wood can make bubbles. Follow the resin maker's instructions for preparing and sealing.
Where the method comes from
Estimates only
These are estimates and general information, not building, safety, legal or professional advice. Materials, coverage, waste and rules vary by product, project and place, so check the maker's instructions and your local rules, and use a qualified person for gas, electrical and structural work.
Rain stopped play. Officially research.