mild steel rectangular tube weight calculator

Enter the dimensions of a mild steel rectangular tube 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%.

Outside width

Outside height

Wall thickness

Length

Number of pieces

Total weight

5.3694kg

= Exact mild steel rectangular tube weight Show in

Weight of one rectangular tube: 5.3694
Volume of one piece: 684
Weight per metre of length: 5.3694 kg/m
Density used: 7850 kg/m3

Show the working

Outside width = 80
Outside height = 40
Wall thickness = 3
Length = 1000
Number of pieces = 1
volume_mm3 = (80*40 - (80 - 2*3)*(40 - 2*3)) * 1000 = 684 000
Volume of one piece = 684 000 / 1000 = 684
Density used = 7850 = 7850
Weight of one rectangular tube = 684 000 * 7850 / 1e9 = 5.3694
Total weight = 5.3694 * 1 = 5.3694
Weight per metre of length = 684 000 / 1000 * 1000 * 7850 / 1e9 = 5.3694

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 = (outer area - inner area) x length, ignoring the corner radii
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 rectangular tube?

Volume = (outer area - inner area) x length, ignoring the corner radii. 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.