Square and rectangular (rectangular) section carbon steel:

Weight per meter: kg/m (kg/m) & lb/ft (lbs/ft) Formula: kg/m = (Oc - 4Wt) * Wt * 0.00785

Where: Oc is the outer perimeter, Wt is the wall thickness; square Oc=4*a rectangle Oc=2a+2b a, b is the side length