Resin calculator
How much epoxy does your pour need? Enter your mold size (or volume), pieces and mix ratio — get resin and hardener amounts in fluid ounces and milliliters, waste buffer included.
Length (in)
Width (in)
Depth (in)
Molds / pieces
Mix ratio
Waste buffer (%)
Dimensions assume a rectangular mold (length × width × depth; 1 cu in = 0.554 fl oz). For irregular molds, fill one with water, pour it into a measuring cup, and use the volume mode. The buffer covers the resin that stays in the cup and stir stick — 10% is realistic.
Your pour
Know what every cast costs
Hivara turns this pour into a recipe — resin, pigment, hardware and mold wear — and shows your true cost and margin on every piece you cast.
Start freeResin pour math, explained
How much resin do I need for my mold?
For a rectangular mold: length × width × depth in inches, times 0.554, gives fluid ounces. A 4×4×1 inch mold needs about 8.9 fl oz of mixed resin. For irregular molds, fill one with water and measure it — water volume equals resin volume.
How do I split resin and hardener for a 2:1 ratio?
Divide the total by three: two parts resin, one part hardener. For 30 fl oz of mixed resin at 2:1 you'd measure 20 oz of resin and 10 oz of hardener. Always use your brand's stated ratio — and measure by volume unless the maker specifies weight.
Should I measure epoxy by weight or volume?
Most craft epoxies specify their ratio by volume, and resin and hardener have different densities — so a 1:1 volume ratio is usually NOT 1:1 by weight. Follow your manufacturer's instructions; when in doubt, measure by volume in marked cups.
How much extra resin should I mix for waste?
About 10% covers what stays in the cup, on the stir stick, and small overpours. Intricate or multi-part pours waste more. Mixing slightly over beats stopping mid-pour to mix again — partial second batches are where curing problems start.
What happens if I get the resin ratio wrong?
Off-ratio epoxy cures soft, sticky or not at all — and there's no fixing it after the pour. Measure carefully in marked cups, scrape thoroughly while mixing, and when a piece matters, do a small test pour with any new resin brand first.
Also useful: the free handmade pricing calculator for what each cast costs and earns — and see how Hivara runs a whole resin business, mold wear and waste included.
Stop pouring your margin into the cup
Hivara stores this as your piece's recipe — every cast draws down resin, pigment and hardware, and shows your true cost and margin per piece.
Start free