Where to buy epoxy resin
Easy to buy and easy to buy the wrong one. The cheapest listing is almost always a coating epoxy, bought by somebody who needed a casting one.
Craft stores and the big marketplaces for a first kit, online craft-resin brands for regular work, and trade or woodworking suppliers by the gallon for anything table-sized. Before price, check three things on the technical data sheet: the maximum pour depth, the mix ratio and whether it is stated by volume or by weight. A gallon kit works out around $15.85 a litre of mixed resin against $44.00 for a craft-store starter — but a cheap coating epoxy for a job that needs casting resin is not a saving at all.
Every craft on this site has one supply question that trips people up. For soap it is lye, for bath bombs it is citric acid, for perfume it is the alcohol and the fact that it cannot go by air. Resin is different: it is easy to buy, stocked everywhere, and shipped without fuss. The problem is that four incompatible products share the word, and the listing you land on is rarely the one your project needs.
The cheapest resin on any marketplace is almost always table top / coating epoxy — it is the highest-volume product and the easiest to make. It is also the wrong resin for anything with depth: 1/8 in per coat against 2 in for a casting system, and pouring past that is a heat hazard rather than a slow cure. That single mismatch accounts for most of the disappointing first batches in this craft.
The second thing listings make hard is comparing price honestly, because some quote a kit and some quote the resin with the hardener sold separately. The table below is per litre of MIXED resin, which is the only number that means anything. Which type to buy covers the systems and the calculator tells you how much you need before you order.
What it actually costs, per litre of mixed resin
Prices are 2026 US midpoints across the mainstream brands and they move — substitute your own. The point of the table is the shape rather than the figures: resin gets dramatically cheaper by the gallon, and the smallest kits are several times the unit price of the largest. Everything here is a kit price, resin and hardener together.
Buy at the scale you are working at
A craft-store kit or a small online one is the cheapest way to find out whether you like this, and it is the most expensive resin per litre you will ever buy. That is a fair trade for one project. What it is not is a way to make a set of coasters, because most starter kits contain a coating epoxy and ship it with molds at a casting depth.
A quart is the right size to test a brand you have not used, because resins differ in viscosity, working time and how they behave with pigment in ways the listing does not describe. Once you have found one you like, gallons roughly halve the price per litre. A kitchen counter, 10 ft takes 6.8 litres for one coat.
A river table, 6 ft is 18.1 litres of deep pour / casting epoxy — several gallon kits, and the point at which woodworking and trade suppliers beat marketplaces on both price and advice. It is also the point at which buying the wrong system costs real money rather than one afternoon.
What to check before you check the price
The single most important line on any data sheet, and the one most listings omit. Table top / coating epoxy is around 1/8 in per coat; deep pour / casting epoxy around 2 in, some to 4 in in a cool room. A brand that does not publish it is a brand that does not want you to compare it.
"2:1" means one mix in a jug and another on a scale, because resin is denser than hardener — 2:1 by volume is 2.20:1 by weight. A good data sheet says which. The mix ratio calculator converts either way, and this is worth knowing before you buy rather than mid-pour.
Some listings price a kit and some price the resin alone with the hardener as a separate line, which makes the second look about a third cheaper than it is. Work everything back to a price per litre of mixed resin before comparing anything — it is the only number that survives the difference.
Clear resin is clear on the day. What separates products is what happens after a year in a sunlit room, and a UV inhibitor is what stops it going yellow. It costs a little more and it is the difference between a table you keep and one you re-pour. For a keyring it does not matter at all.
Buying short is worse than buying long, because you cannot go back mid-pour without leaving a line. Work the volume out first, add the 10% wastage, and round up to the next kit size. Leftover resin keeps for a year in a sealed container; a cold-join line in a counter is permanent.
If a "casting resin" mentions a catalyst measured in drops, a two-minute working time or a strong smell, it is polyester or polyurethane rather than epoxy. Both are real products for other jobs and neither is what a clear craft casting wants. The comparison guide covers them.
Buying well
Ordering blind is how people end up with a gallon of the wrong thing. A kitchen counter, 10 ft is 6.8 litres per coat and a river table, 6 ft is 18.1 litres — the calculator does it from your own dimensions in a minute.
Resins differ in viscosity, working time, how they hold pigment and how they smell, and none of that is in the listing. A quart costs a few pounds more per litre and tells you everything a gallon would have taught you expensively.
Every serious brand publishes one and it states the depth, the ratio, the convention and the cure schedule. The product page states that it is crystal clear and easy to use, which every resin claims. If there is no data sheet, that is information too.
They are formulated as a pair and are not interchangeable between brands or even between systems from the same brand. Mixing one maker's resin with another's hardener does not give a slow cure — it gives no cure.
Uncured epoxy is a skin sensitiser and the sensitivity is cumulative, so the habit has to start on the first bottle rather than the tenth. A box of nitrile gloves costs almost nothing next to a gallon of resin, and it is the purchase people put off until they have been handling it bare-handed for a month.
Resin crystallises in the cold — it goes cloudy or grainy in the bottle, which looks like a fault and is reversible by standing the bottle in warm water. Sealed and above about 15 °C, a kit keeps for a year and often longer.
Work out how much before you order
Enter your project and the calculator gives the volume in litres and US gallons, the resin and hardener split, and a cost at whatever your kit price actually is.
Open the epoxy calculator →Print the pour-depth card
Maximum pour depth and cure windows by resin type — the number that cracks a casting. Free.
Estimates, not advice. Every figure on this page is computed from published reference values and standard measures, so your own inputs, equipment and conditions will move it. Nothing here is professional advice — talk to a qualified professional before acting on it.