How to Calculate the Unit Weight of Steel Bars
Builders use steel bars to construct residential, commercial, and industrial buildings. Different steel bars have different diameters and weights. Before you start working with them, it is mandatory to calculate the weight of steel bars. It is crucial for creating the bar bending schedule. But how to calculate the unit weight of steel bars?
This blog post will uncover how to calculate it and why it is essential in the construction industry.
Method 1 to Determine Unit Weight of Steel Bars
The first step of construction should be budget estimation. After that, the next step should be to calculate the unit weight of the steel bars.
Professionals estimate the budget for steel considering the following facts:
100 meters 20 mm ø bar
100 feet 16mm ø bar
ø=Diameter of Steel Bar
Why Is It Necessary to Measure the Weight of Steel Bars When We Have This Method?
Suppliers who deal in steel bars cannot understand the notation given above. They measure steel bars in weight. Therefore, measuring the steel bars' weight after steel bars cost estimation is essential. Additionally, it is also essential for contractors to order steel bars in the following units:
Kg
Quintal
Ton
Formula to Determine Steel Weight
Steel Bar Weight Formula= W = D²L/162
In formula
W = Weight of steel bars.
D = Diameter of steel bars in mm.
L = Length of bars in meters.
Let’s take an example!
A steel bar is 60 meters long and 12 mm in diameter. Calculate its weight.
Data:
D = 12 mm.
L= 60 m.
Formula:
W = D²L/162
Solution:
W = 12² x 60/162
W= 53 kg
Result:
The 60m long and 12mm diameter steel bar weighs 53 kg.
Unit Weight of Steel Bars Calculation
To get the steel bar unit weight, put a 1-meter length for each diameter of the steel bar in the same formula.
6 mm ø bar = 6² x 1/162 = 0.222 kg/m
8 mm ø bar = 8² x 1/162 = 0.395 kg/m
10mm ø bar = 10² x 1/162 = 0.617 kg/m
12mm ø bar = 12² x 1/162 = 0.888 kg/m
16mm ø bar = 16² x 1/162 = 1.580 kg/m
20mm ø bar = 20² x 1/162 = 2.469 kg/m
Total Weight of Steel Bars Calculation
To get the total weight of steel bars, multiply the length of bars by the unit weight determined using the above technique.
For Instance
The steel bar is 1000m long and has a diameter of 20mm. Its total weight will be calculated as follows:
1000 x 2.469 = 2469 kg.
Using the same method, you can find the unit weight of different steel bars.
Calculate the Steel Bars' Unit Weight in Feet
Before that, we calculate the unit weight in the meter. But you can also calculate it in feet.
The formula to find the steel bar unit weight in feet is:
W= D²L/533
In formula:
D = Diameter of bars in mm.
L = Length of bars in foot.
Method 2 to Determine Unit Weight of Flat Steel Bars
You have already understood that, first, budget estimators make a takeoff sheet and estimate the steel bars for a particular construction project. Next, the unit weight of the steel bar is determined. And after that, experts calculate the total weight of steel bars.
Calculate the Unit Weight of the Steel Flat Bar
Suppose the density of mild steel is 7850 kg/m3. Moreover, experts measure the length and width of mild flat steel in millimeters.
In this case, the formula to find steel bar weight is:
Weight of steel bar = Volume of steel Bar x Density of steel
And
Weight of steel Flat bar = (Length x width x thickness) x 7850
Now Take an Example
An MS steel flat bar is 40mm wide and 20mm thick. Find its unit weight.
Data:
Width= 40mm
Thickness= 20mm
Formula:
Weight of steel bar = Volume of steel Bar x Density of steel
Weight of steel bar = (Length x width x thickness) x 7850
Solution:
Unit Weight of steel bar = (1 x .040 x .020) x 7850
Unit Weight of steel bar = 6.28kg/m
Result:
The 40mm wide and 20 mm thick flat steel bar unit weight is 6.28kg/m.
Calculate the Unit Weight of Steel Rods
Now, take the density of the steel rod as 7850 kg/m3. In this case, measurements are taken using diameter in millimeters.
The suitable formula for this case is:
Weight of steel bar = Volume of steel Bar x Density of steel
And
Weight of steel rod = (Cross-sectional area of steel rod x Length) x 7850 kg/m3
Put Values:
Weight of steel rod = (3.14 x (D2 /4) x L) x 7850 kg/m3
Weight of steel rod = (D2 x 6162.25L)/1000000
Weight of steel rod= D2L x 0.006162 = D2L / 162.28
For Results in Meter:
Weight of Steel Bar = [ D2L / 162.28]
For Results in Feet:
Weight of Steel Bar = [ D2L / 533]
Now, if you want to determine the unit weight, L, the length of the steel rod becomes unity.
Let’s Take Another Example
The diameter of steel bars is 10mm and 12mm. Calculate the unit weight.
Data:
Diameter = 10mm
Diameter = 12mm
Formula:
Weight of Steel Bar = [D2L / 162.28]
Solution:
Unit weight of 10mm dia bar = (10x10x1)/162.28
Unit weight of 10mm dia bar = 0.616kg
Unit weight of 12mm dia bar = (12x12x1)/162.28
Unit weight of 12mm dia bar = 0.8874kg
Final Words
In this blog, we found that there is no fixed method to calculate the unit weight of steel bars. It totally depends on the cross-sectional area of rods and bars. Therefore, it is essential to get assistance from experts in the industry to get accurate calculations.
















