BIZOMAT MAKEOS · Materials
Stock Volume and Mass
What is the theoretical mass of this stock geometry?
Estimate mass for rectangular stock, solid round bar or round tube using an explicitly supplied density.
Open the calculatorRuns in your browser. No account needed.
How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Shape | choice | Select the constant cross-section of the stock. |
| Length | mm | Overall length of the stock. |
| Width / outside diameter | mm | Width for rectangular stock; outside diameter for round stock. |
| Thickness / wall thickness | mm | Rectangular thickness or tube wall; ignored for solid round bar. |
| Density | kg/m³ | Material supplier density at the relevant condition; default is illustrative. |
What each input means
Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.
What this means: Shape
- What it is
- The constant cross-section of the stock: rectangular bar or plate, solid round bar, or round tube. It decides which dimensions are used.
- Units and format
- Choose one of 3 options from the list: Rectangular stock; Solid round bar; Round tube.
- Example
- The form opens with “Rectangular stock” selected as a worked example. Choose the option that matches your case.
- Get it right
- Square and rectangular hollow sections are not covered; use the tube option only for round tube.
What this means: Length
- What it is
- The overall length of the piece of stock, along its constant cross-section.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.001 mm to 1000000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 1000 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Mass is directly proportional to length.
- Get it right
- Use the cut length including any allowance if you are weighing blanks.
What this means: Width / outside diameter
- What it is
- For rectangular stock, the width of the section; for round bar and tube, the outside diameter.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.001 mm to 1000000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 100 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Mass rises in proportion to width for plate, and with the square of diameter for round bar.
- Get it right
- For round stock enter the diameter, not the radius.
What this means: Thickness / wall thickness
- What it is
- For rectangular stock, the thickness of the section; for round tube, the wall thickness. It is not used for solid round bar.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.001 mm to 1000000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 10 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Plate mass is directly proportional to thickness.
- Get it right
- For a tube the wall must be less than half the outside diameter.
What this means: Density
- What it is
- The mass per unit volume of the stock material, from the material supplier for the relevant grade and condition.
- Units and format
- Enter a number in kg/m³: kilograms per cubic metre. The form accepts 0.001 kg/m³ to 100000 kg/m³. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 7850 kg/m³ as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Mass is directly proportional to density.
- Get it right
- Enter kg/m³; a value in g/cm³ needs multiplying by 1000.
Method and formulas
- Rectangular area = width × thickness. Round area = π × diameter² / 4.
- Tube inside diameter = outside diameter − 2 × wall; area = π × (outside² − inside²) / 4.
- Volume (m³) = area (mm²) × length (mm) / 10⁹. Mass = volume × density. Example: 1000 × 100 × 10 mm at 7850 kg/m³ is 7.85 kg.
Limitations
- Uniform cross-section and density only; ignores tolerances, weld beads, coatings and removed features.
- Theoretical mass is not a rated lifting load or a substitute for weighing.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- material weight
- bar mass
- tube mass
- plate mass
Who it is for
- Estimators
- Designers
- Fabricators
What you get
- Cross-sectional area
- Volume
- Theoretical mass
Interpreting the result
- Include allowances for purchasing and handling only when supported by the actual stock and task.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 66–87, 380–384. Topic reference; no source tables or recommended settings are reproduced.
Learn the Concepts Behind This Tool
These BIZOMAT Library readings explain the method this tool uses, with worked examples.
Method explained here · Library collection
Areas, volumes and masses for the workshop: estimating material, weight, coatings and lifts
In Practical Mathematics for Engineering and Manufacturing
What it covers: How to calculate areas, volumes and masses of plates, bars, tubes, tanks and welds, use densities and mass-per-metre figures, and apply them to quoting, coating, handling and lifting.
BIZOMAT tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.