Crucible Capacity & Dimension Calculator
Estimate the geometric internal volume of a cylindrical or tapered crucible from its inside dimensions. Use the result to organize a drawing or quotation request.
Step 1 Define the inner cavity
Enter internal dimensions, not the outside diameter or overall external height. Rounded corners, stepped bases and other internal features are not included.
This leaves an empty height above the calculated fill level. It does not recommend a safe charge volume.
Step 2 Geometric results
- Geometric brimful capacity
- Volume below your selected fill height
- Unfilled geometric volume
Dimensions used
No selected freeboard means zero empty height in the geometric model. Brimful capacity is not a recommended loading condition or a manufacturing tolerance.
Copy the summary into your inquiry. Include the charge, atmosphere, temperature cycle and a dimensional drawing. Calculated volume is supporting information, not a complete product specification.
Calculations run in this browser. Inputs are not saved automatically or sent as analytics events. The inquiry link contains no calculation parameters; nothing is submitted automatically.
Formulas and unit definitions
Normalize all dimensions to millimeters. Cylinder: V = πD²H / 4. Circular frustum: V = πH(Dt² + DtDb + Db²) / 12. D is internal diameter; Dt and Db are internal top and bottom diameters; H is internal height.
For your freeboard height F, 0 ≤ F ≤ H; fill height h = H − F. The diameter at the fill level is Db + (Dt − Db)h/H. The volume below that level is πh(Db² + DbDfill + Dfill²) / 12; for a cylinder it is πD²h / 4. Half a tapered cavity’s height is not generally half its capacity.
1 cm = 10 mm; 1 inch = 25.4 mm exactly. 1 mL = 1 cm³ = 1,000 mm³. Both frustum diameters must be positive. Pointed cones and rounded or stepped cavities are outside this version’s model.
Illustrative geometry examples
A 40 mm internal diameter × 50 mm internal depth cylinder has approximately 62.83 mL brimful geometric capacity. A frustum with top diameter 60 mm, bottom diameter 40 mm and height 50 mm has approximately 99.48 mL capacity. With 25 mm user-selected freeboard, its fill-level diameter is 50 mm and the volume below that height is approximately 39.92 mL.
These are arithmetic examples, not stock sizes, safe loading limits or operating recommendations.
Common questions
Does 1 mL equal 1 cm³?
Yes. The tool shows the same geometric volume in either unit.
Can I calculate from outer dimensions?
Not reliably without a complete internal profile. Wall thickness, base thickness and internal features affect capacity.
Does this tell me how much molten metal is safe to load?
No. Safe loading and application suitability require process-specific review.
Why is half the height not always half the capacity?
A tapered cavity changes cross-sectional area with height. The tool integrates that changing geometry.