Unit Weight of 10mm , 8mm, 12mm and other rebar

0.617 If you were looking for just weight of 10mm rebar its 0.617, If you want to know a simple trick with which you can calculate weight of any TMT rebar read the article below. in this article we will see how to calculate the weight of 1m of any rebar or Unit Weight of rebar and then we will calculate the weight of commonly used rebar.

How to calculate Unit Weight of TMT rebar

There is a Simple Formula for the calculation of unit weight of any rebar:

d2/162 ( Diameter square divided by 162 ) That’s It.

Just Square the diameter and divide it by 162.

So weight of 10mm bar = 10*10/162 (Ten Squared divided by 162)

                                       = 100/162

                                      = 0.617 kg/m

Lets see another example

Weight of 8mm bar = 8*8/162 (Eight Squared divided by 162)

                               = 64/162

                               = 0.395 kg/m

Similarly we can calculate unit weight of any tmt rebar. Below is a table of unit weight of commonly used rebars. All of these weight are calculated with the same formula

Table for UnitWeight of commonly used rebars

Diameter of TMT rebarWeight of 1m of TMT rebar (unit weight of rebar)
8mm0.395 Kg/m
10mm0.617 Kg/m
12mm0.483 Kg/m
16mm1.561 Kg/m
20mm2.469 Kg/m
25mm3.858 Kg/m
28mm4.839 Kg/m
32mm6.321 Kg/m
36mm8.000 Kg/m
40mm9.876 Kg/m
50mm15.432 Kg/m
Unit weight of commonly used rebar

Congratulations now you know how to calculate weight of 1m length of any bar, next step is to learn to Estimate the quantity of rebar.

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Lets learn where D2/162 came from

As we know that Density is Mass/Volume

Density of Steel is 7850Kg/m3

Mass=Density * Volume

= 7850*Volume

Now Here Volume area*length

area is area of a circle Pi d2/4 (rebar has a circular cross sections)

Because D is in mm for a rebar we will Convert D=d/1000

and Length is 1m

Unit Weight = 7850 *(d/1000)2/4

Solving this will give us:

Unit Weight = d2/162.2

For Simplicity

Unit Weight = d2/162 Kg/m


To recap In this article we learned about the weight of 1m rebar also known as Unit Weight of Steel Reinforcement bar. We learned a simple formula to calculate unit weight of rebar. D Squared divided by 162, simply taking diameter of any rebar(Steel Reinforcement bar) and divide it by 162, using this simple formula we calculated the unit weight of 8mm, 10mm, 12mm, 16mm, 20mm, 25mm, 28mm, 32mm, 36mm, 40mm and 50mm rebars.

The exact weight of rebar depends upon its size shape and grade of steel used, a circular bar will have a different weight as compared to square rebar.

We also learned how the formula of d squared divided by 162 is derived form the simple formula that we learned in out basic science class in school, Density = Mass/ volume.

Why do you need to know Unit Weight of rebar

There are a lot of places where you will use weight of steel reinforcement, the first place you will use it is for quantity estimation, as a site engineer you need to have a basic idea of how much steel is being used in any construction project. When you begin a project having proper estimates helps you to fill tender prices, second place you use unit weight is when you buy rebar, steel reinforcement is bought in weight. And last place it is used is while preparing bar bending schedule.