Estimate resin for silicone molds, casting molds, trays, blocks, and simple mold cavities with waste and cost guidance.
Sphere Resin Calculator
Sphere molds use different geometry from round flat molds. This page gives a dedicated input for ball-shaped castings so users are not forced to approximate a sphere as a cylinder.
Enter your measurements
Example inputs
Default dimensions, allowances and prices are example inputs. Replace them with your measurements and product label. Leave unknown product limits blank.
Sphere resin estimate
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Start with the inputs to generate an order-ready estimate.
- Raw volume
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- Conservative
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- Projected cost
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- Part A / Part B
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- Layer guidance
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- Kits to buy
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- Standard
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- Product fit
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Why This Estimate Changed
What moved the number
- Enter the form values to see raw volume, buffer, and recommendation.
Next Step
Match the result to the right resin class
Use the estimate to narrow the resin class first. Then confirm product limits, cure behavior, and measurement assumptions before you make a buying decision.
Measurement diagram
How much resin does a sphere mold need?
Sphere volume is 4/3 × π × radius³, so resin needs grow fast with size: a 2 in (5 cm) sphere holds about 69 ml (2.3 fl oz) and a 4 in (10 cm) sphere about 549 ml (18.6 fl oz) before waste. The table adds the calculator's default 10% for the pour spout, trimming, and cup loss.
| Inside diameter | Raw resin | With 10% waste |
|---|---|---|
| 1 in (2.5 cm) | 8.6 ml (0.29 fl oz) | 9.4 ml (0.32 fl oz) |
| 1.5 in (3.8 cm) | 29 ml (0.98 fl oz) | 32 ml (1.1 fl oz) |
| 2 in (5.1 cm) | 69 ml (2.3 fl oz) | 76 ml (2.6 fl oz) |
| 3 in (7.6 cm) | 232 ml (7.8 fl oz) | 255 ml (8.6 fl oz) |
| 4 in (10.2 cm) | 549 ml (18.6 fl oz) | 604 ml (20.4 fl oz) |
| 6 in (15.2 cm) | 1,853 ml (62.7 fl oz) | 2,039 ml (68.9 fl oz) |
Full spheres only. For a half-sphere (dome) mold, use half of each value.
Diameter controls the volume cubically
A solid 4 cm diameter sphere has volume 4π × 2³ ÷ 3 = 33.510 mL. Ten identical spheres with 10% waste need 368.61 mL. Doubling the diameter makes eight times the volume, not twice. A half-sphere or hollow insert is not a full sphere; use the actual cavity capacity for those shapes. Confirm the product's mass, depth and temperature limits before casting.
Product data before mixing
Use the exact product documentation for mixing basis, maximum layer depth, mixed batch volume and cure or recoat conditions. A dimensional estimate and a purchase allowance do not supply those material limits.
What this calculator covers
- Uses sphere diameter for ball-shaped resin molds.
- Better fit than a round-table calculator for full 3D casts.
- Shows raw volume, buffered quantity, and cost.
- Useful for art spheres, paperweights, ornaments, and ball molds.
How to measure or set the inputs
- Choose inside geometry for a regular shape, or use a known cavity capacity where that mode is available.
- Set the number of identical pieces; the main quantity is the total batch, with a separate loss allowance.
- Check the raw quantity against a hand calculation or a product's published mixed capacity.
- Enter product ratio, limits and total kit mixed yield only when confirmed; purchase quantity is not a batch-mixing instruction.
Common mistakes that cost money
- Using a circle area formula for a full sphere.
- Entering circumference instead of diameter.
- Ignoring overflow or sprue material.
Project checklist before you buy
- Confirm the mold or surface is sealed before mixing resin.
- Measure depth twice at the deepest point of the project.
- Add extra material for waste, seepage, and edge soak-in.
- Confirm the resin type matches the intended pour depth.
- Prepare cups, stir sticks, gloves, and a level work surface.
FAQ
Questions people ask before buying epoxy
Can this estimate half-sphere molds?
The form calculates a full sphere. For a half sphere, use half the recommended amount and keep a waste buffer.
Is diameter measured inside the mold?
Yes. Use the inner cavity diameter, not the outside silicone mold size.
What if the shape is an ornament with a hollow insert?
Subtract the insert volume if known, or test with water and dry the mold completely before casting.
Related Pages
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Reviewed · Calculation notes and corrections