How do I measure my mould volume?

Measure the internal dimensions (length, width, depth) in centimetres. For irregular moulds, fill the mould with water, then pour the water into a measuring jug to find the volume in ml.

Why add a waste allowance?

Resin sticks to mixing cups, stir sticks, and some is lost during pouring. A 10% waste allowance is standard. For small projects, increase to 15% as proportionally more is lost.

How heavy is cured resin?

Epoxy resin has a density of about 1.1 g/ml, so 100 ml of resin weighs about 110 grams when cured. This is useful for estimating the weight of finished pieces.

Should I mix resin by volume or weight?

Always follow your resin manufacturer's instructions. Most 1:1 epoxy resins can be mixed by volume, but some use a ratio by weight. Inaccurate mixing is the most common cause of curing problems.

Can I resin objects that contain water?

No. Fresh flowers, leaves and other organic items must be fully dried before casting in resin. Moisture causes cloudiness and can prevent proper curing. Use silica gel to dry flowers first.

CraftCalcs

Resin Volume Calculator — Mould Volume in ml

Calculate the total resin volume needed for moulds of various shapes.

Mould Shape

Length

Width

Depth

Waste Allowance

Resin Cost Per Litre

Optional

How We Calculate This

How the Calculation Works

The volume is calculated using standard geometric formulas:

Rectangle: length x width x depth. Circle: pi x radius² x depth. Oval: pi x (length/2) x (width/2) x depth. Triangle: 0.5 x base x height x depth.

Since 1 cm³ = 1 ml, the result is in millilitres. The waste percentage is added, then converted to grams using resin density (1.1 g/ml for epoxy).

Frequently Asked Questions

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Last updated: 2025-02-20

All calculations are estimates. Always verify quantities before purchasing materials.