Resin has a costing quirk no other craft quite matches: a meaningful slice of every pour never becomes product. Cup residue, stir sticks, overpour, the occasional failed cast: if your price only covers the resin that ends up in the mold, the rest comes out of your margin. Here's the math that fixes it.
What a cast really costs
A resin keychain, costed honestly:
- Epoxy resin + hardener (0.9 oz incl. waste): about $0.98
- Pigment + glitter: about $0.22
- Keychain hardware: about $0.35
- Mold wear (amortized): about $0.15
- Packaging: about $0.25
$1.95 per piece. Two lines make this real where most resin pricing is fantasy: the waste allowance inside the resin line (pours consume 10–20% more than mold volume; the free resin calculator builds it in), and the mold line. A $14 silicone mold good for ~80 casts adds real cents to every piece; amortize it and replacements fund themselves.
Failures are a cost, not a surprise
Ghosting, bubbles, a bad demold: a few percent of casts fail, and the survivors have to pay for them. Bake an expected failure rate into your per-piece cost, and log actual failures so the rate stays honest. Sellable seconds can become their own discounted product; unsellable ones are already priced in.
The formula for resin
- Small pieces (keychains, coasters): 4–6× materials; our $1.95 keychain at $9 carries a 78% margin that funds the failures and the finishing time
- Statement pieces (trays, art): mostly labor. Sanding, polishing and finishing hours dominate, so price those hours at a real rate
- Customs: quote from the recipe (resin, pigment, hardware, hours) and add a custom premium, since one-off colors can't be batched
Resin pricing mistakes to avoid
- Pricing off mold volume: pours consume more than the mold holds, every time
- Free molds: every cast wears the mold; someone pays for its replacement
- Ignoring finishing time: a "$2 keychain" with 15 minutes of sanding isn't a $2 keychain
- Copying mass-produced resin prices: imported pieces aren't hand-mixed, hand-finished or yours
The resin makers who earn are the ones tracking the KPIs that matter: cost per cast, failure rate, margin by colorway. Keepsel for resin artists keeps each piece's true cost current from its recipe, and from the Maker plan Suli can tell you which pieces earn. The free pricing calculator will tell you today whether your bestseller actually earns.