Resin Mix Ratio Calculator: Part A and B by Volume or Weight
Split a batch into Part A and B by volume or by weight (100:45), or find B for the A you have.
My resin mixes by
Volume
Weight
Volume
Weight
Volume
Weight
Part A (resin), parts
From the label: 100:45 by weight = 100 and 45.
Part B (hardener), parts
I know
The
batch
I
need
Part
A
have
The batch I need
The Part A I have
The batch I need
The Part A I have
Batch weight (oz)
Part A
6.9 oz (196 g)
Part B
3.1 oz (88 g)
Batch
10 oz (283 g)
Part A by volume, about
5.7 fl oz (170 ml)
Part B by volume, about
3 fl oz (88 ml)
Same ratio by volume, about
1.93:1
Part A: 6.9 oz (196 g)
Part B: 3.1 oz (88 g)
Estimates. Follow your product’s technical data sheet: its mix ratio, pour depth and cure time win. Work with ventilation, nitrile gloves and eye protection.
How it works
Enter the two numbers of your mix ratio, say whether the label means volume or weight, and the batch you need. You get Part A and Part B, and with the densities the same batch the other way.
Example: 100:45 by weight and a 300 g batch: Part A = 300 × 100 ÷ 145 = 206.9 g, Part B = 300 × 45 ÷ 145 = 93.1 g.
Have 200 g of Part A left? At 100:45 it needs 200 × 45 ÷ 100 = 90 g of Part B. At 2:1 by volume, 16 fl oz of Part A takes 8 fl oz of Part B.
Frequently asked questions
What is the difference between a ratio by weight and by volume?
By weight you weigh each part on a scale (100:45 means 45 g of hardener for every 100 g of resin). By volume you measure in cups (2:1 means two cups of resin to one of hardener). Resin and hardener weigh different amounts per cup, so the two numbers are not the same.
How do I turn a weight ratio into a volume ratio?
Divide each part by its density. 100:45 by weight with densities 1.15 and 1.00 g/ml: 100 ÷ 1.15 = 86.96 and 45 ÷ 1.00 = 45, so about 1.93:1 by volume.
What happens if I mix the wrong ratio?
Off-ratio epoxy can stay soft, sticky or cloudy, and adding more hardener does not make it cure faster. Measure carefully and follow the ratio on your product’s data sheet.
Where do I find the density of my resin?
On the technical data sheet or safety data sheet, as density or specific gravity (g/ml or g/cm³). Most epoxy resins are about 1.1 to 1.2 and hardeners about 0.95 to 1.05.