How To Calculate The Unit Weight Of Steel Bars

In this post, I’ll show you how to calculate the unit weight of steel bars.

When you estimate the required steel quantity for your projects you get them as length.

For example, 16mmØ bar — 1000 feet.

But steel is sold as kilograms or quintals or tons.

To convert the length of steel bars into weights you need to know the unit weight of different diameter bars.

In this post, I’ll show you the process of calculating the weight of steel bars.

From this calculation process, I’ll generate a formula that you can use to convert any size of steel bar’s length into weight.

I’ll also show you how to get the unit weight of different diameter bars using the formula.

Let’s see the…

Process Of Calculating The Weight Of Steel Bars

Let’s say, you want to know the weight of 1000 meters long 16mmØ bar.

Here,

• Length of the bar (L) = 1000 meter
• Diameter of the bar (d) = 16mm or 0.016 meter

First, calculate the cross-sectional area of the bar.

The formula is,

= ℼd²/4

= ℼ × (0.016)²/4
[ℼ = 3.14]

= 0.00020096 sq.meter

Now, Calculate the weight of the bar.

And the formula is,

= Area × Length × Density

As we know, the density of steel is 7850 kg/m³

So, the weight of the bar is,

= 0.00020096 × 1000 × 7850

= 1577.536 Kilogram.

This is the general process of knowing the weight of steel bars.

With the process, you can also make a…

Formula For Calculating The Weight Of Steel Bars In Meter

Let’s say,

• The length of the bar = L meter
• The diameter of the bar = D millimeter or 0.001D meter

First, calculate the cross-sectional area of the bar.

The formula is,

= ℼd²/4

= ℼ × (0.001D)²/4
[ℼ = 3.14]

= 0.00000314D²/4 sq.meter

Now, Calculate the weight of the bar.

And the formula is,

= Area × Length × Density

So, the weight of the bar is,

= 0.00000314D²/4 × L × 7850
[Density = 7850 kg/m³]

= 0.00616225 D²L

Remembering this formula is a little bit difficult. So, you can express it this way:

Look:

In this formula,

D is the diameter of the bar which should always be in millimeters and L is the length of the bar which should be in meters.

Remember this.

Using this formula, you can also know the…

Unit Weight Of Rebar In Meter…

If you consider, Length (L) = 1 meter.

Let’s see…

For 10mmØ bar,

= (10² × 1)/162

= 0.617 kilogram.

For 12mmØ bar,

= (12² × 1)/162

= 0.888 kilogram.

Similarly, For 16mmØ bar,

= (16² × 1)/162

= 1.58 kilogram.

For easily converting the length of steel bars into the weight during estimating, make a list of unit weight of steel bars according to their diameters that you use frequently in your projects. Like this:

These are the unit weight of steel bars in meters.

But what if you want to know the…

Formula For Calculating The Weight Of Steel Bars In Feet

As you know from the above discussion, the formula for calculating the weight of steel bar is,

= D²L/162

Here,

• D = Diameter of bars in millimeter, and
• L = Length of bars in meter.

If you convert L into feet, it’ll be,

= 3.28L feet.

Now use that in the formula,

= D²×3.28L/162

= D²L/531.36

For easy remembering, we can say,

= D²L/532

Look:

In this formula,

D is the diameter of the bar which should always be in millimeters and L is the length of the bar which should be in feet. Remember this.

Using this formula, you can also know the…

Unit Weight Of Rebar In Foot

If you consider, Length (L) = 1 foot.

Let’s see…

For 10mmØ bar,

= (10² × 1)/532

= 0.188 kilogram.

For 12mmØ bar,

= (12² × 1)/532

= 0.270 kilogram.

Similarly, For 16mmØ bar,

= (16² × 1)/532

= 0.481 kilogram.

For converting the length of steel bars into weight easily during estimating, make a list of unit weight of steel bars according to their diameters that you use frequently in your projects. Like this:

These are the unit weight of steel bars in feet.

If we summarise all the things that we’ve discussed above, it’ll look like this:

Editor’s Note: This post was originally published in March 2021 and
has been updated for accuracy and comprehensiveness.