Bonbon Shell Calculator
Calculate chocolate needed for bonbon shells based on mold cavity volume and shell thickness. Includes bottom cap, filling volume, and waste estimates.
About this calculator
This calculator treats each bonbon cavity as a sphere to work out how much chocolate forms the outer shell versus how much space is left inside for filling. It first converts the cavity's volume into an equivalent sphere radius (using V = (4/3)πr³ solved for r), then subtracts your chosen shell thickness from that radius to get an inner radius. The volume of that smaller inner sphere is the filling space; the difference between the outer and inner sphere volumes is the shell itself, which gets multiplied by chocolate's density (1.3 g/mL) to arrive at chocolate weight per shell. A thinner shell (say 1.5mm) leaves more room for ganache or caramel filling and gives a softer bite, while a thicker shell (up to 5mm here) gives more snap but less filling capacity — the tradeoff every chocolatier balances.
On top of the shell itself, the calculator separately estimates a thin bottom cap (a fixed 0.5mm-thick disc across the cavity's circular base area) that seals the bonbon once it's filled, since real bonbon molds are open on one side during shell-forming and get capped afterward. A flat 10% waste allowance is added across shells and caps combined, covering the chocolate left on the mold, piping bag, and scraper. One important simplification: real bonbon cavities are rarely true spheres — they're often domed, teardrop, or faceted shapes — so treating cavity volume as spherical is a practical approximation that gets shell weight in the right ballpark rather than an exact figure for every mold geometry.
Inputs
Results
Total Chocolate Needed
120.65 g
How to Use This Calculator
- Enter the number of mold cavities and cavity volume in mL.
- Set shell thickness in mm (typical: 1.5–2.5 mm).
- The calculator shows total chocolate needed, per-shell amounts, bottom cap chocolate, waste allowance, filling space per bonbon, total filling weight, and finished bonbon weight.
- Pre-coat mold, fill cavities with tempered chocolate, invert to drain shells, then fill and cap once shells are set.
How the result changes with Mold Cavities
| Mold Cavities | Total Chocolate Needed |
|---|---|
| 12 | 60.32 g |
| 18 | 90.49 g |
| 36 | 180.97 g |
| 60 | 301.62 g |
What each input means
- Mold Cavities
- Total number of bonbon cavities across all your molds. Standard professional molds have 21-28 cavities.
- Cavity Volume
- Total volume of each mold cavity in milliliters. Standard bonbon cavities are 7-10 mL. Measure by filling with water and weighing.
- Shell Thickness
- Desired chocolate shell thickness in millimeters. Standard bonbons use 1.5-2.5mm shells. Thinner = more filling, thicker = more snap.
How this is calculated
Worked example, using the default values
- Identify Input ParametersMold Cavities = 24, Cavity Volume = 8, Shell Thickness = 2 = 3 input(s) provided
- Calculate Total Chocolate NeededTotal Chocolate Needed120.65 = 120.65
- Calculate Chocolate per ShellChocolate per Shell4.26 = 4.26
- Calculate All ShellsAll Shells102.24 = 102.24
Engine last updated . Checked against 1 independently-derived test — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does the calculator treat my mold cavity as a perfect sphere?
Treating the cavity volume as a sphere lets the calculator derive an equivalent radius using V = (4/3)πr³, then subtract shell thickness from that radius to find the inner (filling) volume by the same formula. Real bonbon cavities are often domed, teardrop, or faceted rather than perfectly round, so this is a practical approximation that gets shell weight in the right ballpark rather than an exact figure for every mold geometry.
How much does shell thickness change how much filling I can fit?
Shell thickness is subtracted directly from the equivalent outer radius to get the inner radius, and because sphere volume scales with the cube of radius, even a small thickness change has an outsized effect on inner (filling) volume. A thinner shell like 1.5mm leaves noticeably more room for ganache or caramel and gives a softer bite, while pushing thickness toward 5mm gives more snap but shrinks the filling space fast.
Why is the bottom cap chocolate calculated separately from the shell?
The shell calculation only covers the hollow dome formed while the mold is open on one side; real bonbon molds get filled with ganache afterward and then sealed with a flat bottom cap. The calculator models that cap as a fixed 0.5mm-thick disc across the cavity's circular base area, multiplied by chocolate density, and adds it to the total separately from the shell chocolate.
What does the 10% waste allowance cover here?
The waste figure is 10% of the combined shell-plus-cap chocolate subtotal, added on top as extra to source. It represents chocolate left behind on the mold after inverting to drain excess, chocolate stuck to the piping bag or bowl, and scraper residue — losses that happen during shell-forming and capping regardless of how carefully you work.
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