Steel is available as plate, pipe, round bar, square bar, flat bar, hexagonal bar, rebar, hollow tube and angle steel. The right steel weight calculation formula helps estimate purchasing costs, machining stock, freight and quotations.
This guide uses nominal dimensions and a common steel density of 7.85 g/cm3 to calculate theoretical weight.
1. Steel Weight Formula Units
1.1 Dimensions
L is length in meters. D is diameter; A and B are sides; W is width; T is thickness. Section dimensions are in millimeters.
1.2 Result
Each formula returns kilograms and represents theoretical rather than guaranteed actual weight.
2. Steel Plate and Pipe Weight
2.1 Steel Plate
6 m x 1.51 m x 9.75 mm = 693.43 kg.
2.2 Steel Pipe
114 mm OD x 4 mm wall x 6 m = 65.10 kg.
3. Steel Bar and Rebar Weight
3.1 Round Bar
20 mm x 6 m = 14.81 kg.
3.2 Square Bar
50 mm x 6 m = 117.75 kg.
3.3 Flat Bar
50 x 5 mm x 6 m = 11.78 kg.
3.4 Hexagonal Bar
50 mm across flats x 6 m = 102 kg.
3.5 Rebar
20 mm x 12 m = 29.62 kg.
4. Steel Tube and Angle Weight
4.1 Rectangular Tube
100 x 50 x 5 mm x 6 m = 70.65 kg.
4.2 Square Tube
50 x 50 x 5 mm x 6 m = 47.10 kg.
4.3 Equal Angle
50 x 50 x 5 mm x 6 m = 22.50 kg.
4.4 Unequal Angle
100 x 80 x 8 mm x 6 m = 65.66 kg.
5. Quick Steel Weight Formula Reference
| Shape | Formula | Units |
|---|---|---|
| Plate | 7.85 x L x W x T | L,W m; T mm |
| Pipe | (OD - T) x T x 0.02466 x L | OD,T mm; L m |
| Round bar or rebar | D x D x 0.00617 x L | D mm; L m |
| Square bar | A x A x L x 0.00785 | A mm; L m |
| Flat bar | W x T x L x 0.00785 | W,T mm; L m |
| Hexagonal bar | A x A x L x 0.0068 | A mm; L m |
| Rectangular tube | (A + B) x 2 x T x 0.00785 x L | A,B,T mm; L m |
| Square tube | A x 4 x T x 0.00785 x L | A,T mm; L m |
| Equal angle | A x T x 0.015 x L | A,T mm; L m |
| Unequal angle | (A + B) x T x 0.0076 x L | A,B,T mm; L m |
These formulas support material purchasing, CNC machining preparation, fabrication, inventory, shipping and quotation planning.
Steel Weight Calculation FAQ
What density is normally used for steel?
Ordinary carbon steel is commonly estimated at 7.85 g/cm3, or 7,850 kg/m3.
Why does actual weight differ?
Tolerances, corner radii, scale, coating and composition affect actual weight.
Should purchasing values be verified?
Yes. Use the applicable standard or manufacturer data for important orders.
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