1. Calculate inside diameter
When outside diameter and wall thickness are entered, inside diameter is calculated as:
ID = OD − 2t
When outside diameter and inside diameter are entered, wall thickness is calculated as:
t = (OD − ID) ÷ 2
2. Calculate steel cross-sectional area
Area = π ÷ 4 × (OD² − ID²)
OD and ID are converted to a consistent unit before area is calculated.
3. Apply material density
Mass per length = Area × Density
The default 7,850 kg/m³ value is a theoretical carbon-steel reference assumption. A selected grade, alloy, coating or manufacturer value can differ.
4. Calculate piece and order mass
Piece mass = kg/m × piece length
Total mass = piece mass × quantity
Published reference versus calculated result
For the six initial reference sizes, HowNote also displays a manufacturer-published nominal mass. It remains separate from the calculated mass. The difference can reflect rounding, density assumptions and the basis used by the publication.
What the calculation excludes
- Dimensional tolerances and measured production variation.
- Coating, galvanizing, lining, end preparation and attachments.
- Grade-specific density and chemistry variation.
- Product-specific minimum or maximum mass requirements.