Steel Weight Calculator computes volume, mass, and mass per unit length for common steel shapes (plate, round, square, and pipe) in metric or imperial units.
About units. The calculator uses a single SI state (meters, kilograms, kg/m³) for all math. When you toggle to Imperial, inputs are shown as inches/feet and density as lb/ft³; outputs show lb, lb/ft, and ft³ as primary values with metric shown second.
About density. Presets include carbon steel (~7850 kg/m³), stainless (~8000 kg/m³), aluminum (~2700 kg/m³), and copper (~8960 kg/m³). Choose Custom to edit density directly. Remember that “weight” displayed is mass under standard gravity; we report kg and lb to align with shop-floor practice.
About shapes. Plate uses thickness × width × length. Round and square bars are prismatic solids with constant cross-section along the length. Pipes are hollow rounds defined by outer diameter (OD), inner diameter (ID), and length; the wall area is the difference of the two circular areas.
Conversion / Calculation. The tool computes volume in m³, then multiplies by density (kg/m³) to get mass (kg) and divides by length for mass-per-length (kg/m). On unit toggle, inputs/outputs re-render; the core SI values remain unchanged.
Formulas:
- Plate volume (for volume): V = t · w · L
- Round bar area (for volume): A = (π · d²) / 4, then V = A · L
- Square bar area (for volume): A = a², then V = A · L
- Pipe area (for volume): A = (π/4) · (OD² − ID²), then V = A · L
- Mass (from volume): m = ρ · V
- Mass per length (line weight): m′ = m / L
Examples:
- Example 1 – Plate: t = 10 mm, w = 1000 mm, L = 2.0 m, ρ = 7850 kg/m³ → V = 0.01·1.0·2.0 = 0.02 m³; m ≈ 157.0 kg; m′ ≈ 78.5 kg/m.
- Example 2 – Round bar: d = 20 mm, L = 6.0 m → A = π·0.02²/4 ≈ 3.1416·0.0004/4 = 0.000314 m²; V ≈ 0.001884 m³; m ≈ 14.8 kg; m′ ≈ 2.46 kg/m.
- Example 3 – Pipe: OD = 48.3 mm, ID = 40.0 mm, L = 6.0 m → A = (π/4)(0.0483² − 0.04²) ≈ 0.000598 m²; V ≈ 0.003588 m³; m ≈ 28.2 kg; m′ ≈ 4.70 kg/m.
Corresponding tools. For single-plate pieces, try the Plate Weight Calculator. For beam selection, see Structural Steel Section Properties. For fabrication estimating, use the Welding Cost Calculator.
