Epoxy Resin and Hardener Mixing Ratio Calculator

Balance resin batches for coatings and repairs. Review weight, volume, coverage, waste, and cost instantly. Reduce mixing errors with clear outputs, charts, and downloads.

Calculator Inputs

Enter either a target mixed amount or fill project area and thickness to let the tool estimate batch size from geometry. If both are provided, the larger requirement is used before waste is added.

Example Data Table

Project Basis Ratio Area (m²) Thickness (mm) Coats Waste (%) Required Mix
Self-leveling floor patch Weight 2:1 12.0 1.5 1 8 19.44 L before density conversion
Countertop sealing coat Volume 1:1 4.5 0.8 2 5 7.56 L mixed material
Repair mortar binder Weight 3:1 Manual batch — — 10 5.50 kg adjusted from 5.00 kg

Formula Used

Project Volume (L) = Area (m²) × Thickness (mm) × Coats
Base Required Amount = max(Manual Target, Project Requirement)
Adjusted Requirement = Base Required Amount × (1 + Waste% / 100)
If ratio is by weight: Resin Mass = Total Mass × Resin Parts / Total Parts
If ratio is by weight: Hardener Mass = Total Mass × Hardener Parts / Total Parts
If ratio is by volume: Resin Volume = Total Volume × Resin Parts / Total Parts
If ratio is by volume: Hardener Volume = Total Volume × Hardener Parts / Total Parts
Weight-basis Mix Density = (R + H) / ((R / ρr) + (H / ρh))
Volume-basis Mix Density = ((R × ρr) + (H × ρh)) / (R + H)
Estimated Pot Life ≈ Base Pot Life × (100 / Batch Mass in g)^0.15 × 2^((25 − Temperature)/10)

Pot life changes quickly with ambient temperature, container shape, filler load, and total batch mass. Treat the pot-life result as a planning estimate, not a replacement for manufacturer technical guidance.

How to Use This Calculator

  1. Select whether the product ratio is specified by weight or by volume.
  2. Enter the resin and hardener parts exactly as listed on the product sheet.
  3. Add a target mixed amount, or enter project area, thickness, and coats.
  4. Fill resin and hardener densities to improve weight-volume conversion accuracy.
  5. Add waste percentage for rollers, containers, surface absorption, and transfer loss.
  6. Optionally enter kit size, kit price, temperature, and base pot life.
  7. Press the calculate button to view the results above the form.
  8. Use the CSV and PDF buttons to save your batch summary.

Frequently Asked Questions

1) Should epoxy ratios be measured by weight or volume?

Use the method specified by the manufacturer. Some systems are labeled by weight, while others are labeled by volume. Switching methods without density conversion can create soft cures, brittle finishes, or tacky surfaces.

2) Why do density values matter in epoxy mixing?

Density connects mass and volume. When resin and hardener have different densities, a 2:1 weight ratio is not the same as a 2:1 volume ratio. Accurate density values improve material planning and conversion quality.

3) How much waste allowance should I add?

For clean, flat surfaces, 3% to 5% may be enough. For textured substrates, repairs, or transfer-heavy mixing, 8% to 12% is often safer. Always review site conditions before final ordering.

4) Why does pot life drop with larger batches?

Epoxy curing is exothermic. Larger batches hold heat, speed up the reaction, and shorten working time. Wide trays can help dissipate heat better than deep mixing cups.

5) Can I mix partial kits safely?

Yes, if the ratio is measured accurately and the product sheet allows field splitting. Use clean tools, precise scales or measuring containers, and mix thoroughly by scraping the sides and bottom.

6) What happens if I add too much hardener?

Extra hardener does not make epoxy cure better. It can weaken the final film, leave uncured residue, reduce chemical resistance, and cause performance issues. Stay on ratio.

7) How do I estimate coating coverage from thickness?

A thickness of 1 mm over 1 square meter uses 1 liter of material. Multiply area by thickness in millimeters and by number of coats to estimate theoretical liters before waste.

8) Is this calculator enough for final site approval?

It is a planning tool. Final approval should still follow the product datasheet, substrate preparation rules, environmental limits, and any test area results from the actual job site.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.