Round Bar Weight Calculator
Solid bar weight from diameter — steel, stainless, aluminum, brass and copper
Round bar weight grows with the square of the diameter — double the diameter and the bar is four times heavier. That is why a Ø20 mm steel bar is a comfortable 2.47 kg/m while a Ø80 mm bar is a crane-hook 39.5 kg/m. This calculator applies weight = π/4 × D² × length × density with the exact density of your chosen alloy.
For quick steel estimates machinists use the classic rule: kg/m ≈ D²/162 with D in millimeters. Ø25 bar: 625/162 ≈ 3.86 kg/m. The calculator refines this with the actual grade density — meaningful for stainless, brass, and copper bar.
Typical uses: estimating billet weight for machining jobs, bar stock purchasing, and checking lathe load capacity before chucking large diameters.
Frequently Asked Questions
How do I calculate round bar weight per meter?
Weight per meter = π/4 × D² × density. For steel there is a handy shortcut: kg/m ≈ D²/162 with D in mm. A Ø30 mm steel bar: 900/162 ≈ 5.55 kg/m.
What does a Ø50 mm steel bar weigh?
About 15.4 kg per meter (50²/162). A standard 3-meter bar is therefore roughly 46 kg — a two-person lift.
Does the weight formula change for hex bar?
The area formula changes: for a hexagon measured across flats, A = (√3/2) × s². A hex bar weighs about 10% less than a round bar of the same across-flats dimension. This calculator supports hex bars directly — select the hexagonal profile.