Hexagonal Bar Weight Calculator
Weight of hex bar from across-flats dimension — steel, brass and more
Hexagonal bar is measured across the flats (AF). Its cross-section area is A = (√3/2) × s², where s is the across-flats size, so weight = (√3/2) × s² × length × density. This calculator uses the exact density of your chosen alloy — important for brass and stainless hex, common in fasteners and machined parts.
A 24 mm AF steel hex bar weighs about 3.84 kg/m. A hex bar weighs roughly 10% less than a round bar of the same across-flats diameter, which is why hex stock is efficient for bolt heads, nuts and spacers.
Frequently Asked Questions
How do I calculate hex bar weight?
Weight per meter = (√3/2) × s² × density, with s the across-flats size in mm. A 24 mm AF steel hex bar: 0.866 × 576 mm² × 7.85 g/cm³ ≈ 3.92 kg/m.
Is hex bar measured across flats or across corners?
Across the flats (AF) — the distance between two parallel faces, the same dimension a wrench spans. Across-corners is larger and not used for sizing.
Why use hex bar instead of round?
The flats let a wrench or chuck grip it, so hex is standard for fasteners and machined parts. It also weighs about 10% less than round bar of the same across-flats size.