Resin Calc

Epoxy Weight to Volume Calculator

Resin and hardener have different densities, so a weight is not a volume. Convert either way for Part A, Part B or mixed epoxy, and see the answer in metric and imperial at once.

Weight & Volume Converter

Convert
fl oz
Material

Converted

Result

35.05oz

In every unit

Millilitres
946.4 ml
Fluid ounces
32 fl oz
Grams
993.7 g
Ounces
35.05 oz

Using 1.05 g/ml

How to Convert Epoxy Weight to Volume

Weight and volume are linked by density, and epoxy has more than one. Part A resin is typically around 1.10 grams per millilitre, Part B hardener nearer 0.95, and mixed epoxy lands in between at roughly 1.05. Using the wrong one is where conversions go astray.

  1. 1

    Decide which material you are converting

    Converting a whole batch uses the mixed density. Converting one side of the kit, which is what a by weight mix ratio requires, needs that component's own density. Picking the wrong material introduces an error of several percent, which is enough to matter on a ratio.

  2. 2

    Use the data sheet figure when you have it

    The defaults here are typical values, not your product. Most manufacturers publish a specific gravity, and entering it makes the conversion exact rather than approximate. Density also drifts slightly with temperature, though not enough to worry about at room temperature.

  3. 3

    Multiply for weight, divide for volume

    Volume in millilitres multiplied by density gives grams. Grams divided by density gives millilitres. Everything else is unit conversion: one US fluid ounce is 29.5735 millilitres, and one ounce is 28.3495 grams.

  4. 4

    Watch the two kinds of ounce

    A fluid ounce measures volume and an ounce measures weight, and they are not interchangeable for epoxy. A fluid ounce of mixed resin weighs about 1.09 ounces, so treating them as equal builds an error straight into your mix.

Why Mix Ratios by Weight and by Volume Differ

A product labelled 2:1 by weight is not 2:1 by volume, and mixing it as though it were will leave the cure soft.

The two parts are not equally dense

Resin is heavier than hardener for the same volume. Take a 2:1 by weight product with resin at 1.10 and hardener at 0.95. Two grams of resin occupy 1.82 ml while one gram of hardener occupies 1.05 ml, so by volume the ratio is closer to 1.73:1, not 2:1.

The error compounds with batch size

On a small art pour the difference is a few millilitres and may still cure. On a river table it can be hundreds, which is comfortably enough to leave sticky patches that never harden and cannot be repaired.

Check which the label means

If the data sheet does not say, look for a mention of mixing by weight or a note about using a scale. When a product gives both ratios they will be different numbers, which is itself the clue. The epoxy volume calculator has a weight mode that handles this properly.

Weight and Volume Questions

How much does a gallon of epoxy weigh?

A US gallon of mixed epoxy weighs roughly 3975 grams, or about 8.8 pounds, at a typical mixed density of 1.05 grams per millilitre. Resin alone is heavier and hardener alone is lighter, so check which you mean. To price that gallon, use the epoxy cost calculator.

Is a fluid ounce of epoxy the same as an ounce?

No. A fluid ounce is a volume and an ounce is a weight. A fluid ounce of mixed epoxy weighs about 1.09 ounces because the resin is denser than water. Mixing the two up is a common source of ratio errors.

What is the density of epoxy resin?

Part A resin is commonly around 1.10 grams per millilitre and Part B hardener around 0.95, giving a mixed density near 1.05. These vary between brands, so use your data sheet figure when precision matters.

Can I mix epoxy by weight if the label gives a volume ratio?

Only if you convert it properly, and it is usually safer not to. Measure the way the label specifies. If you must convert, use each part's own density rather than the mixed figure, because the ratio changes between the two systems.

Do I need a scale to mix epoxy?

Not for a volume ratio, where graduated cups are fine. For a ratio given by weight a scale is essential, and one reading to a tenth of a gram is inexpensive and far more accurate than trying to convert in your head.