What does a 2:1 mix ratio mean?

A 2:1 ratio means 2 parts resin (Part A) to 1 part hardener (Part B). So for 300 g total you would use 200 g of resin and 100 g of hardener. Ratios can be by weight or by volume — always check your product data sheet.

Should I mix by weight or by volume?

Most professional resin users prefer mixing by weight using a digital scale because it is more accurate. Volume mixing is acceptable when a scale is not available, but note that resin and hardener often have different densities, so equal volumes do not equal equal weights.

What happens if the ratio is off?

Incorrect ratios result in a resin that does not cure fully — it may stay tacky, remain soft, or have weak mechanical properties. Always measure carefully and follow the manufacturer's specified ratio.

What is the typical ratio for epoxy resin?

Common epoxy ratios are 1:1 or 2:1 by volume, and 100:43 by weight for some marine-grade systems. Always check your product's technical data sheet — ratios vary by formulation.

Can I enter a ratio like 100:43?

Yes. Use the custom ratio option and enter 100 for Part A and 43 for Part B. The calculator handles any numeric ratio.

Resin Mixing Calculator

Enter your resin type, mix ratio, and desired total amount to get exact part A (resin) and part B (hardener) quantities by weight or volume.

Resin Mix Settings

Resin Type (Preset)

Mix Ratio (Part A : Part B)

Part A (Resin)

Part B (Hardener)

Tip: check your product data sheet for the correct ratio by weight or volume.

Measure By

Weight Volume

Unit

Total Amount to Mix

Results

Enter settings and click Calculate.

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Summary

This resin mixing calculator determines exact Part A (resin) and Part B (hardener) amounts for any mix ratio and total quantity. It supports epoxy, polyester, and polyurethane resin presets as well as fully custom ratios, and works in grams, ounces, milliliters, or fluid ounces.

How it works

Select your resin type (epoxy, polyester, polyurethane, or custom).
Enter the mix ratio — Part A to Part B — either by weight or by volume.
Choose your unit: grams, ounces, milliliters, or fluid ounces.
Enter the total amount you want to mix.
The calculator instantly shows how much Part A (resin) and Part B (hardener) to measure out.

Use cases

Calculating exact epoxy resin and hardener amounts for a river table or countertop pour.
Mixing the right ratio of polyester resin and hardener for fiberglass layup.
Portioning polyurethane foam or casting resin for mold filling.
Scaling up or down from a small test batch to a full project pour.
Verifying you have enough resin and hardener on hand before starting.
Working out how many grams or milliliters to pull from large containers.

Frequently Asked Questions

Last updated: 2026-06-14 · Reviewed by Nham Vu