Epoxy Calculator
Work out your epoxy resin and hardener quantities
Choose your application, enter your area or casting volume, and get an instant resin/hardener split and kit recommendation.
Common questions
Epoxy or polyester resin — which do I need?
Epoxy has stronger adhesion and lower shrinkage, and is the standard choice for carbon fibre, casting and bonding. Polyester is cheaper and standard for general GRP laminating (see our Polyester Resin Calculator).
Why does the mix ratio matter?
Epoxy cures through an exact chemical reaction between resin and hardener. Too little or too much hardener leaves the epoxy soft, tacky or brittle — always mix by the ratio on the technical data sheet, not by eye.
Can I speed up or slow down the cure?
Choosing a fast or slow hardener changes cure time — the mix ratio itself shouldn't be changed to do this. Temperature affects working time too: warm conditions shorten it, cool conditions extend it.