mild steel hex bar weight calculator

Enter the dimensions of a mild steel hex bar and this works out its volume and weight. Plain carbon structural steel such as A36, S275 or 1018. Alloying moves the density by well under 1%.

Across flats

Length

Number of pieces

Total weight

4.248 94kg

≈ Rounded mild steel hex bar weight Show in

Weight of one hex bar: 4.248 94
Volume of one piece: 541.266
Weight per metre of length: 4.248 94 kg/m
Density used: 7850 kg/m3

Show the working

Across flats = 25
Length = 1000
Number of pieces = 1
volume_mm3 = sqrt(3)/2 * 25^2 * 1000 = 541 266
Volume of one piece = 541 266 / 1000 = 541.266
Density used = 7850 = 7850
Weight of one hex bar = 541 266 * 7850 / 1e9 = 4.248 94
Total weight = 4.248 94 * 1 = 4.248 94
Weight per metre of length = 541 266 / 1000 * 1000 * 7850 / 1e9 = 4.248 94

Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.

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The formula

Volume = (sqrt(3) / 2) x across-flats^2 x length
Weight = volume x density, with density = 7850 kg/m3
One cubic millimetre of a material at 1000 kg/m3 weighs exactly one milligram, so the millimetre-to-kilogram step is a shift of the decimal point rather than a rounded factor.

Plain carbon structural steel such as A36, S275 or 1018. Alloying moves the density by well under 1%.

Dimensions are nominal. Mill tolerances on thickness, and the corner radii on formed sections, both move the real weight by a percent or two.

Every field takes inches or feet as readily as millimetres: change the unit next to it and the conversion is done exactly before the arithmetic starts.

Frequently asked

What is the density of mild steel?

7850 kg/m3, which is 7.850 g/cm3. Plain carbon structural steel such as A36, S275 or 1018. Alloying moves the density by well under 1%.

How do you calculate the weight of a mild steel hex bar?

Volume = (sqrt(3) / 2) x across-flats^2 x length. Multiply the volume by the density of mild steel, 7850 kg/m3, taking care that both are in the same unit system.

Can I enter dimensions in inches?

Yes. Each dimension field has its own unit selector, and inch, foot, millimetre, centimetre and metre entries are all converted exactly before anything is multiplied.

Where the numbers come from

Densities are nominal room-temperature values for the grade named, drawn from the usual mill and handbook figures.