How is metal weight calculated?

Weight equals the cross-sectional area of the profile multiplied by its length and the material density. The calculator works in millimetres and grams, so a 25 mm round steel bar one metre long has an area of about 491 mm squared, a volume of 491,000 mm cubed, and at 7.85 g per cubic centimetre weighs roughly 3.85 kg.

Why does my supplier's weight differ slightly?

Mill tolerance on diameter and thickness, plus small variation in alloy density, means real stock can differ a few percent from the nominal figure. Use this result for ordering and shipping estimates, and weigh critical parts directly.

What density should I use for stainless steel?

Common austenitic grades 304 and 316 are about 8.0 g per cubic centimetre, slightly denser than mild steel at 7.85. The dropdown already carries the right value for each listed alloy, so just pick the grade.

How do I calculate a hex bar weight?

Enter the distance across the flats. A regular hexagon has area equal to the square root of three over two times the across-flats dimension squared, which the tool applies automatically before multiplying by length and density.

Can it handle tube and pipe?

Yes. Choose round tube or square tube and enter the outer size plus the wall thickness. The calculator subtracts the inner area, so it returns only the metal weight of the wall, not the enclosed volume.

Metal Weight by Shape Calculator

Knowing the weight of a piece of metal stock before you order or ship it saves money and avoids surprises at the loading dock. This calculator turns a shape, a size, and a length into an accurate weight for twenty common engineering metals, all in your browser.

How it works

Every weight comes from one simple chain: cross-sectional area times length times density. The only thing that changes between profiles is how the area is found.

weight = area x length x density

round bar:    area = pi x (d/2)^2
round tube:   area = pi x (ro^2 - ri^2)
square bar:   area = side^2
square tube:  area = side^2 - (side - 2 x wall)^2
flat bar:     area = width x thickness
hex bar:      area = (sqrt(3) / 2) x across_flats^2

The tool works in millimetres for length and area, and grams for mass. Because density is quoted in grams per cubic centimetre, it divides density by 1000 to match the millimetre-cubed volume, then multiplies through. Weight per metre and weight per piece fall straight out of the same numbers.

Tips and notes

Density is the value that most affects your answer, so pick the exact alloy rather than a generic “steel” or “aluminum.” A 6061 aluminum part weighs about a third of the same shape in steel, while copper and brass are slightly heavier than steel and titanium is roughly half.

For hollow profiles, the wall thickness must be less than half the outer size or there is no metal left to weigh. The calculator guards against that and asks you to fix the input. Treat the final figure as a close estimate: rolling and extrusion tolerances mean two bars cut to the same nominal size can still differ by a few percent.