TAHA Engineering Toolsby TAHA Knowledge Lab

Material Weight

Round Bar Weight Calculator

Weight per metre and per piece of solid round bar or rod.

Inputs

Solid round bar with diameter d at the end and length L along the side.dL — length
Solid round bar of diameter d and length L. Weight = π d² ÷ 4 × L × density. Diagram not to scale.

Density used: 7,850 kg/m³ — nominal value used in steel section mass tables, e.g. EN 10210-2 and EN 10219-2 (7.85 kg/dm³).

Result

Weight per bar
14.7969
Weight per length
2.46615
Total weight
14.7969
Cross-section area
314.159
Density used
7,850

A 20 mm round bar in carbon / mild steel weighs 2.46615 kg/m, so one 6 m bar weighs about 14.7969 kg.

Educational estimate — check the assumptions below.

About this calculator

This calculator finds the weight of solid round bar, rod and shafting from its diameter and length. It gives the weight per metre (useful for price lists and stock control) and the weight of each piece.

Formula

A = πd² ÷ 4    m = A × L × ρ

d = diameter (m), L = length (m), ρ = density (kg/m³).

Quick rule for steel (ρ = 7850 kg/m³): weight per metre ≈ d² ÷ 162.2 kg/m, with d in mm.

Worked example

A 20 mm carbon steel bar, 6 m long:

  • Area = π × 0.020² ÷ 4 = 3.1416 × 10⁻⁴ m²
  • Weight per metre = 3.1416 × 10⁻⁴ × 7850 = 2.466 kg/m
  • One 6 m bar = 2.466 × 6 = 14.80 kg
  • Quick rule: 20² ÷ 162.2 = 2.466 kg/m ✓

Assumptions and limitations

  • A solid, perfectly round bar at nominal diameter.
  • Ribbed reinforcing bar (rebar) is specified by nominal mass per metre in its product standard; use this result only as an estimate for rebar.
  • Densities are typical values; check supplier data for the exact grade.

References

  • EN 10060 covers dimensions and tolerances of hot-rolled steel round bars; steel mass based on 7.85 kg/dm³.