Resin Calculator
Work out the millilitres and grams of mixed resin a mould needs, and split it into part A and part B at your ratio.
At a glance
- What you enter
- Mould shape, Length, Width, Diameter, Pour depth, Height of the cylinder, Shape factor, How many pieces?, Waste allowance, Resin density, How is the mixing ratio quoted?, Part A in the ratio, Part B in the ratio
- What you get
- Total volume for all pieces, Total mixed volume including waste, Total weight of the mixed batch, Part A by weight, Part B by weight
- Formula shown
- Yes, every step, right below your results.
- Cost and privacy
- Free, no account needed, and nothing you type is stored.
See worked examples ↓ Read the FAQ ↓ Share this calculator ↓
Results are estimates for general information only, always verify with a professional or official source before acting on them.
How to use the Resin Calculator
- 1 Enter Mould shape
- 2 Enter Length (cm), Rectangular moulds only.
- 3 Enter Width (cm), Rectangular moulds only.
- 4 Enter Diameter (cm), Circular and cylindrical moulds. The tool uses half of this as the radius.
- 5 Enter Pour depth (mm), For a domed or irregular shape this is the height of the dome at its highest point.
- 6 Enter Height of the cylinder (cm), Cylindrical moulds only.
- 7 Enter Shape factor, Domed or irregular shapes only. The fraction of the flat volume that the real shape holds. About 0.6 for a gentle dome, 0.8 for a nearly flat casting.
- 8 Enter How many pieces?
- 9 Enter Waste allowance (%), Resin left in the cup and on the stick. A 10 to 15 percent allowance is normal.
- 10 Enter Resin density (g/ml), Most epoxy products are about 1.05 to 1.2 grams per millilitre. A filler or a heavy pigment raises it.
- 11 Enter How is the mixing ratio quoted?, Volume ratios are the usual wording for craft epoxy. A weight ratio is not the same as a volume ratio, because the two parts usually have different densities.
- 12 Enter Part A in the ratio, The first number. A 2:1 ratio is part A = 2, part B = 1.
- 13 Enter Part B in the ratio, The second number.
- 14 Press Calculate. You get Total volume for all pieces, Total mixed volume including waste, Total weight of the mixed batch, Part A by weight, Part B by weight, and every intermediate step stays visible under "How is this calculated?"
- 15 Change one number at a time to see what moves the result, that is usually the most useful thing a calculator can tell you.
Worked examples
Real numbers run through this calculator. Open any example to load it into the form above and change it.
10 cm square coaster mould
A rectangular mould 10 cm by 10 cm, poured 2 cm deep, with a 1:1 ratio and no waste allowance.
You enter
- Mould shape
- 1
- Length
- 10 cm
- Width
- 10 cm
- Diameter
- 10 cm
- Pour depth
- 20 mm
- Height of the cylinder
- 10 cm
- Shape factor
- 0.60
- How many pieces?
- 1
- Waste allowance
- 0%
- Resin density
- 1.10 g/ml
- How is the mixing ratio quoted?
- 1
- Part A in the ratio
- 1
- Part B in the ratio
- 1
You get
- Total volume for all pieces
- 200.00 ml
- Total mixed volume including waste
- 200.00 ml
- Total weight of the mixed batch
- 220.00 g
- Part A by weight
- 110.00 g
- Part B by weight
- 110.00 g
200 cubic centimetres, which is 200 millilitres, about 220 grams, split into 100 millilitres of each part.
10 cm round coaster mould
A circular mould 10 cm across, poured 2 cm deep, at the default density.
You enter
- Mould shape
- 2
- Length
- 10 cm
- Width
- 10 cm
- Diameter
- 10 cm
- Pour depth
- 20 mm
- Height of the cylinder
- 10 cm
- Shape factor
- 0.60
- How many pieces?
- 1
- Waste allowance
- 0%
- Resin density
- 1.10 g/ml
- How is the mixing ratio quoted?
- 1
- Part A in the ratio
- 1
- Part B in the ratio
- 1
You get
- Total volume for all pieces
- 157.08 ml
- Total mixed volume including waste
- 157.08 ml
- Total weight of the mixed batch
- 172.79 g
- Part A by weight
- 86.39 g
- Part B by weight
- 86.39 g
A 5 cm radius gives pi times 25 times 2, about 157 cubic centimetres, about 173 grams.
Batch of twelve coasters with waste
Twelve square moulds of 10 cm by 10 cm at 2 cm deep, with a 12 percent waste allowance and a 2:1 ratio.
You enter
- Mould shape
- 1
- Length
- 10 cm
- Width
- 10 cm
- Diameter
- 10 cm
- Pour depth
- 20 mm
- Height of the cylinder
- 10 cm
- Shape factor
- 0.60
- How many pieces?
- 12
- Waste allowance
- 12%
- Resin density
- 1.10 g/ml
- How is the mixing ratio quoted?
- 1
- Part A in the ratio
- 2
- Part B in the ratio
- 1
You get
- Total volume for all pieces
- 2,400.00 ml
- Total mixed volume including waste
- 2,688.00 ml
- Total weight of the mixed batch
- 2,956.80 g
- Part A by weight
- 1,760.00 g
- Part B by weight
- 880.00 g
The moulds hold 2,400 millilitres, and the waste allowance takes the batch to about 2,688 millilitres. Mix in two or three batches rather than one huge one.
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Frequently asked questions
How much resin do I need for a mould?
Is one millilitre of resin the same as one cubic centimetre?
How do I work out the volume of an irregular or domed mould?
Why is a weight ratio not the same as a volume ratio?
Can I pour a deep mould in one go?
Terms used here
Short, plain-language definitions of the words this calculator uses.