Epoxy mix ratio calculator
Enter the mix ratio from the label, by volume or by weight, and the amount you need. You get the resin and hardener amounts, in volume and in weight.
Result
Resin (A), by volume
US fl oz
Hardener (B), by volume
US fl oz
Resin (A), by weight
g
Hardener (B), by weight
g
- With these densities the ratio by weight is not the same as the ratio by volume. Compare the two ratios in the steps below with your data sheet, and use the amounts that match how you measure: volumes for cups, weights for a scale.
| Ratio by volume: parts of B per hundred parts of A | 50 |
|---|---|
| Ratio by weight: parts of B per hundred parts of A | 43.010753 |
| Resin (A), by volume | 21.33 US fl oz |
| Hardener (B), by volume | 10.67 US fl oz |
| Total mix, by volume | 32.00 US fl oz |
| Resin (A), by weight | 703.07 g |
| Hardener (B), by weight | 302.39 g |
| Total mix, by weight | 1,005.46 g |
How it works
Resin and hardener do not weigh the same per cup, so a ratio by volume and a ratio by weight are different numbers for the same product. The calculator turns the ratio you enter into both forms using the density of each part, then splits your amount with the form that matches how you measure. Every amount is shown both as a volume and as a weight.
Formula
Weight = volume × density, and volume = weight ÷ density. A ratio A : B by volume is (A × density of A) : (B × density of B) by weight. A ratio A : B by weight is (A ÷ density of A) : (B ÷ density of B) by volume. For a total T: resin = T × A ÷ (A + B), hardener = T × B ÷ (A + B), using the ratio in the same form as T. For resin R on hand: hardener = R × B ÷ A. Example from one data sheet: 2 : 1 by volume with 9.3 and 8.0 lb per US gallon is 100 : 43 by weight, because 100 × (1 × 8.0) ÷ (2 × 9.3) = 43.
Worked example
The calculator opens with this example; the result above is computed from it.
| Input | Value |
|---|---|
| The amount you enter is | The total mix I want |
| The ratio on the label is | By volume |
| I measure | By volume, in cups |
| Amount, by volume | 32 US fl oz |
| Ratio: parts of resin (A) | 2 |
| Ratio: parts of hardener (B) | 1 |
| Density of the resin (A) | 9.3 lb/US gal |
| Density of the hardener (B) | 8 lb/US gal |
| Resin (A), by volume | 21.33 US fl oz |
| Hardener (B), by volume | 10.67 US fl oz |
| Resin (A), by weight | 703.1 g |
| Hardener (B), by weight | 302.4 g |
32 US fl oz of mix at 2 to 1 by volume is 21.33 US fl oz of resin and 10.67 US fl oz of hardener. With densities of 9.3 lb/US gal and 8 lb/US gal, that weighs 703.1 g and 302.4 g: 43.0 parts of hardener per hundred parts of resin by weight.
Common cases
| Case | Starting values | Resin (A), by volume | Hardener (B), by volume | Resin (A), by weight | Hardener (B), by weight |
|---|---|---|---|---|---|
| Kit labelled two to one by volume, one kilogram weighed on a scale (MAS Deep Pour X densities) | Amount, by weight 1,000 g; Ratio: parts of resin (A) 2; Ratio: parts of hardener (B) 1; Density of the resin (A) 9.3 lb/US gal; Density of the hardener (B) 8 lb/US gal | 21.22 US fl oz | 10.61 US fl oz | 699.2 g | 300.8 g |
| One US quart of a two to one mix, measured in cups (MAS Deep Pour X densities) | Amount, by volume 32 US fl oz; Ratio: parts of resin (A) 2; Ratio: parts of hardener (B) 1; Density of the resin (A) 9.3 lb/US gal; Density of the hardener (B) 8 lb/US gal | 21.33 US fl oz | 10.67 US fl oz | 703.1 g | 302.4 g |
| Five hundred grams of resin already on the scale, two to one by volume (MAS Deep Pour X densities) | Amount, by weight 500 g; Ratio: parts of resin (A) 2; Ratio: parts of hardener (B) 1; Density of the resin (A) 9.3 lb/US gal; Density of the hardener (B) 8 lb/US gal | 15.17 US fl oz | 7.59 US fl oz | 500.0 g | 215.1 g |
| Data sheet ratio of a hundred to forty-four by weight, measured in cups (WiseBond Deep Pour densities) | Amount, by volume 48 US fl oz; Ratio: parts of resin (A) 100; Ratio: parts of hardener (B) 44; Density of the resin (A) 9.3 lb/US gal; Density of the hardener (B) 8.2 lb/US gal | 32.02 US fl oz | 15.98 US fl oz | 1,055.3 g | 464.3 g |
Questions and answers
What is a two to one epoxy ratio by weight?
It is not two to one: resin and hardener have different densities. With a resin of 9.3 lb/US gal and a hardener of 8 lb/US gal, a kit that is 2 to 1 by volume needs 43.0 parts of hardener for every hundred parts of resin by weight. A batch of 1,000 g is then 699.2 g of resin and 300.8 g of hardener. Use the densities on your own data sheet.
How do I measure a two to one mix in cups?
Add the parts and split the batch: two parts of resin and one of hardener make three parts. A batch of 32 US fl oz is 21.33 US fl oz of resin and 10.67 US fl oz of hardener.
The data sheet gives the ratio by weight. Can I still use cups?
Yes, if you know both densities: divide each weight part by its density to get volume parts. For 100 to 44 by weight with a resin of 9.3 lb/US gal and a hardener of 8.2 lb/US gal, a batch of 48 US fl oz is 32.02 US fl oz of resin and 15.98 US fl oz of hardener.
Assumptions and limits
- The starting densities are the values printed on the MAS Deep Pour X technical data bulletin. They are an example, not typical values. Replace them with the figures for your product.
- If your data sheet prints both ratios, by volume and by weight, use those directly; they come from the maker's own measurements. The conversion here is for when only one ratio and the densities are given.
- The total volume is the sum of the two volumes. Any small change in volume when the parts are mixed is ignored.
- Densities on data sheets are measured at a stated temperature and change slightly with it. The effect is small next to measuring errors.
- The calculator does not know any product. The ratio and whether it is by volume or by weight are yours to read from the label.
The result is an estimate for planning, not professional advice.
Sources
- Meridian Adhesives Group (Epoxy Technology): how to convert epoxy mix ratios from weight to volume - divide each part's weight by its specific gravity; worked examples EPO-TEK 353ND and H20Eretrieved 2026-10-12
- MAS Deep Pour X technical data bulletin (revised October 2020): resin density 9.3 lbs/gal, hardener density 8.0 lbs/gal, mix ratio by weight 100A : 43B, by volume 2A : 1Bretrieved 2026-10-12
- WiseBond DEEP Pour epoxy technical data sheet: weight per gallon 9.3 lbs (resin) and 8.2 lbs (hardener), mix ratio 2 to 1 by volume (100 to 44 by weight)retrieved 2026-10-12
- TotalBoat: how to measure epoxy by weight vs. volume - resin and hardener have different densities, so the mix ratio by weight is always different from the mix ratio by volumeretrieved 2026-10-12
- NIST SP 811 Appendix B.9: pound per gallon (U.S.) = 1.198264 E+02 kg/m3; gram per cubic centimeter = 1.0 E+03 kg/m3 (exact)retrieved 2026-10-12
Last updated:
Method in depth: Epoxy mix ratio by volume and by weight: why they differ
Cite this page: Resin Math, “Epoxy mix ratio calculator”, https://resin-math.pages.dev/epoxy-mixing/epoxy-mix-ratio-calculator/ (updated 12 October 2026).
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