We knew that the D²/162.2 formula to calculate the weight of the rounded bar in Kg/m.  But What about the weight of a steel plate or irregular shape?

Basically, any unit weight calculation falls under this broad formula

Unit weight = Volume X Density

Unit Weight of Steel Bars

Steel Bars

From the above formula,  Unit weight of steel bar = Volume of steel bar X Density of steel bar

We know Area of Ciricle = πr (where R=D/2) = πD2/4

Therefore the unit weight of steel per meter = Area of steel X Density of steel X Bar Length

= π(D2/4) x 7850 Kg/m3 x 1m
= 3.14 D2 /4 X 7850 X 1
= (6162.25 D2) / (10002) (since diameter is in mm converting to m -> 1 m = 1000 mm)
= D2 / 162.2

Therefore Unit weight of steel bar per metre formula is D2 / 162.2


Example Calculation of Steel Bar

What is the weight of 5m length & 16mm Dia bar?

Unit weight of steel bar = D2 / 162.2 X Lenght of the bar = (162)/ 162.2 X 5 m = 7.89 Kg


How to calculate flat steel bars weight?

flat steel bar

Using the above Broad Formula,

Unit Weight of plate = Area x Density of Steel x Thickness


What is the weight of plate having measurement 5m x 2m and thickness 12mm?

Weight of plate = (5 x 2) x 7850 x 0.012 = 942 Kg

Steel Bar – Unit Weight Chart

Here we listed the steel bar weight chart which often used in the reinforcement.

Dia of Bar Weight in Kg/m
8 0.394
10 0.616
12 0.887
16 1.578
20 2.466
25 3.853
32 6.313

We hope that now you understand the steel bar & steel plate weight calculation. Make use of the calculator.


Bala is a Planning & QS Engineer working at Megha Engineering & Infrastructure Limited. He is the author, editor of Civil Planets.

Write A Comment