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Epoxy · coating & casting

Epoxy resin calculator

Calculate how much epoxy resin you need from area and thickness or mold size, then estimate weight, waste allowance, and safe batch splits.

A practical sample is prefilled so you can calculate volume, weight, and batch size with one click. Everything stays in your browser.

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Settings

Optional. Many epoxies are around 1.05–1.20 g/mL.

0–30%. Adds a margin for mixing loss and left-over material.

Optional. Limit volume per pour to plan multiple mixes.

mm

Use wet film thickness; dry film will be thinner.

Results

Values auto-update as you edit.

Base volume (before waste)
10.00 L / 2.64 gal · 10,000 mL / 338 fl oz
Total volume incl. waste
11.00 L / 2.91 gal · 11,000 mL / 372 fl oz

Per coat: 5.00 L / 1.32 gal · 5,000 mL / 169 fl oz

Base mass (before waste)
11.00 kg / 24.25 lb
Total mass incl. waste
12.10 kg / 26.68 lb

Batch planning

3 batches

Per batch volume: 3.67 L / 0.97 gal

Per batch mass: 4.03 kg / 8.89 lb

Total with waste: 11.00 L (2.91 gal).

Includes a 10% waste allowance and uses metric units.

Keep batches small to control heat; scrape cup walls when mixing.

How to use (3 steps)

  1. Choose Metric or US units, then set resin density and waste allowance.
  2. Pick a mode: surface (area × thickness), rectangular, cylinder, or known volume. Enter the dimensions.
  3. Hit Calculate, review volume & weight, and copy the URL to share the same setup.

A practical sample is prefilled. Press Calculate to generate volume, weight, waste allowance, and batch count.

Epoxy planning: optimize for controlled batches, not just total volume

Total resin demand is only the first decision. Real-world epoxy work is constrained by pot life, ambient temperature, cup geometry, and mixing consistency. A correct total volume can still fail if single-batch size is too large and heat rises quickly. Use this calculator to separate project total from safe batch execution. Plan the number of batches first, then allocate time windows and tools per batch. This reduces waste, improves cure quality, and lowers the chance of rushed pours.

Recommended workflow

Common mistakes

Mini pour example

A project needs 3.2 L total with 10% waste, but safe cup size is 0.8 L. Instead of one large mix, split into four controlled batches and stage tools for each pour cycle. This keeps exotherm manageable and preserves working time. The small extra prep usually prevents expensive rework from partial cure defects.

FAQ

How much waste margin should I add?

5–15% is common. Rough surfaces, fillers, or colored pours may need closer to 20–30% while flat coatings can use less.

What density should I use?

Check the product data sheet. If you do not know it, try 1.10 g/mL. Set density to 0 to skip weight outputs.

Should I split into multiple batches?

Large batches can overheat. Keep each mix below your safe cup size or pot life. Use the max per batch field to split the total.

Does this include fillers or pigments?

Not automatically. If additives materially change mass or volume, include them in your waste or adjustment assumptions.

Should I round up to full kit sizes?

Usually yes. Round up to the next available kit and keep a small contingency for cup loss, edge sealing, and touch-up work.