The principle is the same for any product: weight = section area × length × density. For steel the density is 7.85 g/cm³, so one metre of a section with a 1 cm² area weighs 0.785 kg.
Quick formulas for steel
- Round tube:
kg/m = (D − t) × t × 0.02466 - Square or rectangular tube, sharp corners:
kg/m = (2·(B + H) − 4t) × t × 0.00785 - Sheet:
kg/m² = thickness (mm) × 7.85 - Round bar and rebar:
kg/m = d² × 0.00617 - Square bar:
kg/m = a² × 0.00785 - Flat bar:
kg/m = width × thickness × 0.00785 - Hexagon bar:
kg/m = S² × 0.0068(S = across flats) - Equal angle:
kg/m ≈ t × (2a − t) × 0.00785
For another material, multiply the steel result by the density ratio: aluminium is about 2.9 times lighter (× 0.344), 304 stainless is 1% heavier (× 1.01).
Frequently asked questions
Why does the calculated weight differ from the scale?
Sections are rolled with tolerances. EN 10034 allows mass deviations of ±4% on HEA/HEB/IPE, and sheet is often delivered towards the lower thickness limit. Square tubes have rounded corners, which reduce the weight compared with sharp-corner calculation, which is why the calculator uses the EN 10219 radius.
What is the difference between HEA, HEB and HEM?
All are wide flange H beams. HEA is the light series (depth slightly below the section number), HEB the standard series (depth equal to the number up to 300) and HEM the heavy series, with much thicker flanges and web. For the same size, HEB is about 40% heavier than HEA.
UPN or UPE?
UPN has tapered flanges (the inside of the flange is sloped), UPE has parallel flanges, which makes bolted connections simpler. For the same depth, UPE is usually slightly lighter and wider.
What do S235 and S355 mean compared with OL37 and OL52?
They are the European (EN 10025) names for structural steels. The number is the yield strength in N/mm². The old Romanian OL37 (STAS 500) roughly matches S235JR, and OL52 matches S355J2. See the table in the Converter section.
How many 6 m bars do I need?
Use the Cutting optimization tab: enter the pieces and the calculator arranges them in bars so the offcut is as small as possible, also taking the saw kerf into account.
Can the results be used for structural design?
The calculator gives theoretical weights for estimating, quoting and transport. For structural design consult an engineer and the manufacturer’s data sheets.
Start calculating
All the formulas above are already in the calculator, for 22 product types.