Composites, Fiberglass & Advanced Materials calculator

Resin Mix Ratio Calculator

Use this calculator to confirm resin mix proportions for epoxy, vinyl ester, polyester, gelcoat, adhesive, or tooling resin batches.

What this calculator does

  • Calculate resin-to-hardener or resin-to-catalyst mix ratio for composite resin systems.
  • checking resin, hardener, catalyst, or promoter proportion
  • The result shows the resin-side ratio on the selected reporting basis.

Formula used

  • Resin Mix Ratio = resin base weight or volume ÷ hardener, catalyst, or additive amount
  • Converted resin mix ratio = resin mix ratio × mix-ratio reporting conversion

Inputs explained

  • resin base weight or volume: Use resin side A, base resin, gelcoat, or promoted resin amount from the batch sheet.
  • hardener, catalyst, or additive amount: Use side B, hardener, MEKP, catalyst, promoter, or additive amount on the same weight or volume basis.
  • mix-ratio reporting conversion: Use 1 for direct ratio or another multiplier if the shop reports per 100 parts resin.

How to use the result

  • Use it before batching resin, auditing mix records, or troubleshooting cure, exotherm, tack, or laminate quality issues.
  • Treat the result as a planning estimate until it is checked against the approved laminate schedule, material datasheets, ply books, resin batch records, tool condition, cure logs, inspection results, customer specification, and actual shop observations for the same part family and process.

Common questions

  • What is the resin mix ratio calculator for? Use this calculator to confirm resin mix proportions for epoxy, vinyl ester, polyester, gelcoat, adhesive, or tooling resin batches.
  • What information should I enter? Enter matched resin base weight or volume and hardener, catalyst, or additive amount values from the same coupon, panel, ply kit, batch, or laminate calculation. Use the conversion only when reporting in another basis.
  • What does the result tell me? The result shows the resin-side ratio on the selected reporting basis.
  • When is the result only an estimate? Treat the result as a planning estimate until it is checked against the approved laminate schedule, material datasheets, ply books, resin batch records, tool condition, cure logs, inspection results, customer specification, and actual shop observations for the same part family and process.

Last reviewed 2026-05-12.