Resin volume calculator
Enter the mold shape and size, the depth of the pour, how many pieces and your resin's mix ratio by volume to see how much to mix in milliliters and ounces.
How to use this calculator
A resin pour is a volume: the area of the mold multiplied by the depth you fill it to. For a rectangle the area is length × width; for a round mold it is π × radius², where the radius is half the diameter. In inch mode the calculator converts cubic inches to milliliters (1 cubic inch is 16.387 ml); in centimeter mode, cubic centimeters are already milliliters. It also shows US fluid ounces (1 fl oz is 29.57 ml).
For example, four 4-inch square coasters poured 1/4 inch deep hold 4 × 4 × 0.25 = 4 cubic inches each, about 65.5 ml, or 262 ml for the set. With 10% extra for the mixing cup and overfill, mix about 288 ml.
The total is then split by your product's mix ratio. With a 1:1 ratio by volume, half is resin (part A) and half hardener (part B); with 2:1, two thirds are resin. Many epoxies give the ratio by volume and some by weight; the two are not interchangeable, so follow the label. Thick pours can overheat as epoxy cures, which is why coating epoxies and deep-pour casting resins list a maximum depth per layer. If your depth is more than that, pour in layers.
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Questions about this calculator
How much resin do I need for a coaster?
A 4-inch round coaster 1/4 inch deep holds about 51 ml; a 4-inch square one about 66 ml. Enter your mold size above for the exact figure and add a little for waste.
Can I measure resin by weight?
Only if the product gives a ratio by weight. Resin and hardener often have different densities, so a 1:1 ratio by volume is not 1:1 by weight.