This construction video provides you step-by-step guidelines to calculate the weight of a steel bar in kg per meter i.e. kg/m.

Reinforcing bar abbreviated as Rebar, entirely called reinforcing steel and reinforcement steel. It is a steel bar or mesh of steel wires applied as a tension device in reinforced concrete and reinforced masonry structures to fortify and grasp the concrete in tension. Rebar's surface is frequently patterned to develop a superior bond with the concrete.

Steel bars are mostly used in Automobiles, Heavy Earth Moving Equipments, Tractors, Railways, Aluminium Industry, and Oil & Gas Sector. The Reinforcing Steel Bar is usually available in length of 9m or 12 m. The steel bar diameter applied is diverse and consequently the weight also differs.

In this video, demonstration is given on a cross section steel bar that contains 12 mm dia. In order to convert it to meter, divide it by 1000. So, dia will be 0.012 M. The length of the bar is taken as 1 Meter.

In order to find out the volume, the following formula will be used:-

Volume = π/4 x (D)2 x l = π/4 x (0.012)2 x 1 = 1.130973355 x 10-04
Now, in order to determine the weight of the steel bar in Kg/m, the formula will be volume x density
The density of steel is given as 7850 kg/m3
So, weight of steel bar = 1.130973355 x 10-04 x 7850 = 0.887814 = 0.887 Kg/m

Go through the following video to more clear conceptions.

Video Courtesy : Construction Technology & civil Work