About this calculator
Epoxy Resin Calculator is a free set of tools that works out how much epoxy a project needs, and how to split that total into Part A and Part B. It is built for woodworkers, makers and DIYers who would rather measure once than buy twice.
Why it exists
Almost every epoxy calculator online is run by a company that sells epoxy. Those tools are useful, but they assume you are buying that brand, they assume that brand's mix ratio, and they rarely handle anything unusual. This one is deliberately brand neutral. It takes whatever ratio and pour depth limit your product actually specifies, including odd ratios like 100:83, and it works in metric as well as imperial.
How the maths works
Volume is plain geometry. A rectangular pour is length times width times average depth. A round pour is pi times the radius squared, times depth. That cubic figure is then converted to liquid volume, where one cubic inch is 0.554113 US fluid ounces and one cubic centimetre is one millilitre. The total is split by your mix ratio, either by volume or, if your product is labelled that way, by weight using the density of each part.
What it does not do
It cannot know your product. Maximum pour depth, cure times and whether to mix by volume or weight all come from the technical data sheet for the resin you bought, and those vary a lot between brands. The calculator gives you the numbers. Your data sheet gives you the rules. Treat every result as an estimate and add a waste allowance, because resin always clings to cups and stir sticks.
How it is built
The site is a static web app with no accounts, no database and no tracking of what you type. Every calculation runs in your own browser, so nothing you enter is ever sent anywhere. The formulas live in a small, separately tested module, and the current test suite covers volume, ratio splitting, weight mode, unit conversion and the multi stage river table maths.