Steel Weight Calculator
Steel Is Quoted by Weight Long Before It's Cut to Size
A steel supplier's price sheet is organized by weight per foot, not by the bar or pipe you're picturing, so converting a piece's dimensions into pounds or kilograms is the first real step in pricing any steel purchase. Because steel's density is essentially constant across ordinary carbon steel grades, that conversion is just geometry multiplied by a fixed number.
The Formula
Pipe: Weight = π × (OD² − ID²) ÷ 4 × Length × Density
For a rectangular bar or plate, the calculator multiplies length, width, and thickness (after converting width and thickness from inches or millimeters into the same unit as length) by steel's standard density of 490 lb per cu ft (7,850 kg/m³). For a pipe, it works out the cross-sectional area as the difference between the outer and inner diameter circles, then multiplies by length and density — the same ring-area approach used for any hollow cylindrical section.
Where This Calculation Matters
- Structural fabrication — plate and bar stock for brackets, gussets, and custom structural pieces is priced by weight, so an accurate estimate avoids surprises on a fabricator's quote.
- Pipe and tube purchasing — the wall thickness of a pipe (the gap between inner and outer diameter) drives most of its weight, which is why two pipes of the same outer diameter can weigh very differently.
- Shipping and handling planning — knowing total steel weight in advance matters for crane capacity, truck load limits, and freight cost estimates on larger fabrication jobs.
Worked Examples
| Shape | Dimensions | Weight |
|---|---|---|
| Rectangular bar | 10 ft × 4 in wide × 0.5 in thick | 68.06 lb |
| Pipe | 10 ft, 4 in OD, 3.5 in ID | 100.22 lb |
How to Use This Calculator
- Select Rectangular Bar / Plate or Pipe.
- Select Imperial (in, ft, lb) or Metric (mm, m, kg) units.
- For a bar, enter Width and Thickness. For a pipe, enter Outer Diameter and Inner Diameter.
- Enter the Length.
- Select Calculate to see the total steel weight.
Related Calculations
Sizing a structural steel beam instead of a bar or pipe? The I-Beam Calculator handles the more complex flange-and-web cross-section, and the Structural Beam Calculator covers how that beam performs under load.