This free bar weight calculator from HAGUE FASTENERS LIMITED works out the weight of round bar, square bar, hexagon bar and plate or flat bar, per metre, per piece and for a whole order, in kilograms and pounds. Sizes can be entered in millimetres or inches, and it covers carbon and alloy steels, stainless and duplex steels, nickel alloys, titanium and copper alloys.
Bar and plate weight calculator
Theoretical weight from the nominal size and a typical density for each material. Hexagon bar is sized across flats with sharp corners. Real bar and plate weigh slightly more or less because of rolling tolerances, rounded corners and machining allowance, so add a margin for cutting and machining when ordering.
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Guidance only. Results are approximate and for initial guidance. They are not a substitute for the governing standard, specification or drawing, or for testing. HAGUE FASTENERS LIMITED accepts no liability for decisions made using these tools. Always check critical values against the relevant standard. © 2026 HAGUE FASTENERS LIMITED.
How to use the bar weight calculator
- Choose the shape: round, square, hexagon, or plate and flat bar.
- Choose mm or inches, then enter the diameter, side, across flats size, or thickness and width.
- Enter the length in metres, millimetres, feet or inches, and the quantity.
- Choose the material. For anything not listed, choose “Other” and enter the density.
- The calculator shows the weight per metre and per foot, the weight of each piece and the total. For plate it also shows the weight per square metre, and for hexagon bar the size across corners.
How the bar weight calculator works
Weight is the cross-section area multiplied by the length and the density of the material. The areas are: round bar π × d² / 4, square bar side², hexagon bar 0.866 × across flats², and plate thickness × width. In metric, weight in kg per metre = area in mm² × density in g/cm³ / 1000. For example, 25 mm round bar in carbon steel (7.85 g/cm³) weighs 3.85 kg per metre, and 10 mm steel plate weighs 78.5 kg per square metre.
Densities are typical values for each material. Weights are theoretical: real bar and plate vary slightly with rolling tolerances, rounded corners and machining allowance.
Frequently asked questions
How do I work out the weight of steel bar per metre?
For round steel bar, a quick rule is 0.006165 × d² kg per metre, with d in millimetres. So 50 mm round bar weighs about 15.4 kg per metre. For square bar use 0.00785 × side², and for hexagon bar 0.0068 × across flats².
Is stainless steel heavier than carbon steel?
Slightly. Austenitic stainless steels such as 304 and 316 are about 8.00 g/cm³, compared with 7.85 g/cm³ for carbon steel, so they weigh about 2% more. Nickel alloys such as Inconel 625 and Monel 400 are heavier again, and titanium weighs a little over half as much as steel.
How is hexagon bar measured?
Hexagon bar is sized across the flats, which is the spanner size. The size across the corners is about 1.155 times the across flats size, and the calculator shows it for you.
Can you machine parts from bar in special materials?
Yes. HAGUE FASTENERS LIMITED machines special fasteners and turned parts from bar in alloy steels, stainless and duplex steels, Inconel, Monel, Hastelloy, titanium and other materials, to drawing or specification. Use the button in the calculator to send us your enquiry.
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Need special fasteners made to drawing, sample or specification? Send us an enquiry or call +44 (0)1902 365 865.