Free steel calculator
Round bar weight calculator
Enter the nominal diameter, cut length, and quantity. The calculator shows a theoretical weight you can use for early planning, then carries the estimate into the RFQ if you need a supply review.
Theoretical result
Estimated mass
Based on nominal geometry and the selected density. This is not a scale ticket or order acceptance.
Method
A plain geometry calculation.
kg/m = π ÷ 4 × (diameter in mm ÷ 1,000)² × density in kg/m³At the default density, this is approximately diameter² × 0.006165 kg/m when diameter is in millimetres. The calculator uses the full π-based expression rather than the rounded shortcut.
Source for the default density: European Commission Joint Research Centre, steel design handbook, Table 2.
Reuse the same basis
Weight table, CSV, and JSON
The downloadable dataset covers nominal solid round bar diameters from 1 mm through 400 mm in one-millimetre steps.
Before buying or shipping
Where the estimate stops.
Questions buyers ask
Round bar weight FAQ
What formula does the round bar weight calculator use?
It calculates the circular cross-sectional area from nominal diameter, multiplies by length and the selected density, and reports the result as theoretical mass.
Why is 7,850 kg/m³ the default steel density?
The European Commission JRC steel-design handbook lists 7,850 kg/m³ as the unit mass used for steel design calculations. The calculator keeps density editable because this is an engineering convention, not a certificate value for every heat and grade.
Can this result be used as shipment or invoice weight?
Not by itself. Diameter tolerance, scale, surface removal, end condition, and measured material density can change actual mass. Shipment, quotation, and settlement follow the method agreed in the accepted order.