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**What Is Unit Weight?**

The** unit weight** of any **substance** is defined as the** ratio of mass** or** weight per unit volume**. It is generally measured in** pound/ft**, gm/cm or, **kg/cm **or kg/m, etc.

The **unit weight of materials** is different depending on **their composition** & ingredient materials **properties**. It gives an **idea about** the heaviness or** lightness of materials.**

**What Is Unit Weight of Steel?**

As we know, **steel **is one of the most used **construction **materials. Finding out the **unit weight **of the **steel **bar before its **application **is **equally importan**t.

The steel bars are **majorly **used as **reinforcement** to strengthen the **tensile property** of concrete **structures.**

The** density of steel** is around **7850 kg/m3** or 7.85 g/cm3 or** 490 lbs/ft3** or **13231 lbs/yd3**.

The **steel weight** is generally measured in** Kg**, **Ton**, and **pound.**

**Different Diameters of Steel Bars Used In Construction**

T**here **are various **steel diameters** used in construction are **8mm, 10 mm, 12 mm, 16 mm, 20 mm, 25 mm, 32 mm, and 40 mm.**

The **steel diameter **used for **normal residentia**l, commercial, and **office building **construction is **8 mm to 20 mm.**

The **steel diameter** of **25 mm to 40 mm** is used for **heavy construction** like **bridges**, dams, and **retaining walls.**

**The Formula Used To Calculate Weight of Steel**

The **formula** used to calculate the **unit weight of steel bars** is **D²/162**. Where, **D = Dia. Of steel **bars, **162 i**s a **constant value.**

**Derivation of D2/162 Formula**

Consider a steel bar with a diameter of D and a length is L.

**Weight of Steel Bar (W) = Unit Weight of Steel Bar (γ) x Volume (V)**

W = γ x V

W = πD²/4 x γ ** (V = πD²/4)**

**As known that Steel unit weight is about 7850 kg/m3 (γ)**

**W = πD²/4 x 7850**

Here, **D is steel** diameter in **mm**, and the** density of steel is in kg/m3.** To make a c**onstant value **in the same **unit **we will convert Dia. Of steel in **mm to m.**

**D****²**** mm / 1000****²**

**W = π/4 x D²/1000****²**** x 7850**

**W = D²/162.28 kg/m**

**W = D²/162 kg/m**

**Read More: 10 Different Types of Steel | Carbon Steel & Alloyed Steel**

**How to Calculate Unit Weight of Steel Bars**

The **unit weight of the steel bar** is calculated by **dividing the weight** of the steel bar by its volume. For calculating the **unit weight of steel bars** consider the **unit length of 1 meter** for all** steel diameter steel.**

**1. Unit Weight of 8 mm steel bar**

**Dia of Steel = 8 mm, Length of Steel bar = 1 m**

**Unit weight of 8 mm steel bar**

= D²/162

= 8² /162

= 8×8/162

=64/162

**= 0.395 kg/m³**

**The unit weight of 8 mm dia. Steel bar is 0.395 kg/m³**

**8mm steel weight** per meter is 0.395 kg

8mm steel bar unit weight in feet = 0.12 kg/ft

**For example,**

8mm steel rod weight 40 ft

= 0.12×40

= 4.8 kg

So, an 8mm steel rod weight of **40 ft is 4.8 kg**

**2. Unit Weight of 10 mm Dia. Steel Bar** (10mm steel bar weight)

**The following is the method to calculate the 10mm steel bar weight**

Dia of Steel = 10 mm, Length of Steel bar = 1 m

**Unit weight of 10 mm steel bar**

= D²/162

= 10² /162

= 10×10/162

= 100/162

**= 0.617 kg/m³**

**The unit weight of 8 mm dia. Steel bar is 0.617 kg/m³**.

**10mm steel weight** per meter is** 0.617 kg **

So, **10mm steel bar weight **is 0.617 **kg/m³**.

**3. Unit Weight of 12 mm Dia. Steel Bar**

Dia of Steel = 12 mm, Length of Steel bar = 1 m

**Unit weight of 12 mm steel bar**

= D²/162

= 12² /162

= 12×12/162

= 144/162

**= 0.890 kg/m³**

**The unit weight of 8 mm dia. Steel bar is 0.890 kg/m³**.

**12mm steel weight** per meter is **0.890 kg **

**4. Unit Weight of 16 mm Dia. Steel Bar**

Dia of Steel = 16 mm, Length of Steel bar = 1 m

**Unit weight of 16 mm steel bar**

= D²/162

= 16² /162

= 16×16/162

= 256/162

**= 1.58 kg/m³**

**The unit weight of 8 mm dia. The steel bar is 1.58 kg/m³**.

**16mm steel weight** per meter is 1.58 kg

### 5. Unit Weight of 20 mm Dia. Steel Bar

Dia of Steel = 20 mm, Length of Steel bar = 1 m

**Unit weight of 20 mm steel bar**

= D²/162

= 20² /162

= 20×20/162

=400/162

**= 2.46 kg/m³**

**The unit weight of 20 mm dia. The steel bar is 2.46 kg/m³**.

**20mm steel weight** per meter is **2.46 kg **

### 6. Unit Weight of 25 mm Dia. Steel Bar

Dia of Steel = 25 mm, Length of Steel bar = 1 m

**Unit weight of 8 mm steel bar**

= D²/162

= 25² /162

= 25×25/162

=625/162

**= 3.85 kg/m³**

**The unit weight of 25 mm dia. The steel bar is 3.85 kg/m³**.

**25mm steel weight** per meter is** 3.85 kg **

**7. Unit Weight of 32 mm Dia. Steel Bar**

Dia of Steel = 32 mm, Length of Steel bar = 1 m

**Unit weight of 32 mm steel bar**

= D²/162

= 32² /162

= 32×32/162

=1024/162

**= 6.32 kg/m³**

**The unit weight of 32 mm dia. The steel bar is 6.32 kg/m³**.

**32mm steel weight** per meter is **6.32 kg **

### 8. Unit Weight of 40 mm Dia. Steel Bar

Dia of Steel = 40 mm, Length of Steel bar = 1 m

**Unit weight of 40 mm steel bar**

= D²/162

= 40² /162

= 40×40/162

= 1600/162

**= 9.87 kg/m³**

**The unit weight of 8 mm dia. The steel bar is 9.87 kg/m³**

**40mm steel weight** per meter is **9.87 kg **

## Unit Weight of Different dia. of Steel Bars Used In Construction

Dia of Steel Bar | Length | Unit Weight |

8 mm | 1 m | 0.395 kg/m |

10 mm | 1 m | 0.610 kg/m |

12 mm | 1 m | 0.89 kg/m |

16 mm | 1 m | 1.58 kg/m |

20 mm | 1 m | 2.46 kg/m |

25 mm | 1 m | 3.87 kg/m |

32 mm | 1 m | 6.32 kg/m |

40 mm | 1 m | 9.87 kg/m |

**Unit Weight of Steel Bars**

**How to Calculate Weight of Steel Bars on Construction Site**

**The following **are the **steps to be followed** to find out the **quantity of steel is availabl**e on the **construction site** or steel is** loaded in the truck** at the time of delivery.

**Step: 1 Recognize the Different Dia. of Steel Available in Stock**

Firstly, we have to** recognize** the different **dia. Steel** bars are **available on site.**

Suppose, there are **8 mm,** 10 mm, **16 mm**, and **20 mm steel bars** are available on site.

**Step: 2 Count the Number of Steel Bars of Each dia. Of Steel**

Now, **count **the numbers of **steel bars** in** each dia**. Steel bars are **available on site.**

**For example,**

8 mm = 80 nos.

10 mm = 120 nos.

12 mm = 50 nos.

16 mm = 60 nos.

20 mm = 30 nos.

**Step: 3 Find out the Unit Weight of Steel Bars**

Now** calculate** the **unit weight of steel bars** by taking a **1 m length** sample of each **dia of steel and weighing it.**

This **weight of 1 m length** sample will directly give you the **unit weight** of that steel bar dia in **kg/m.**

The **unit weight of steel bar**s is as follows,

8 mm = 0.395 kg/m

10 mm = 0.620 kg/m

12 mm = 0.89 kg/m

16 mm = 1.58 kg/m

20 mm = 2.46 kg/m

**Step: 4 Calculate the Total Weight of Each dia Steel Bars**

From **unit weight** and numbers of **steel bars**, calculate the **total weight** of each dia **steel bar **available on site.

**For Example,**

**1. 8 mm Dia steel Nos = 80, Unit Weight of 8 mm Dia Steel = 0.395 kg/m**

Total **Weight** of **8 mm dia stee**l = **Nos x Unit Wt x Length of Steel (12 m)**

= 80 x 0.395 x 12

**= 379.2 kg**

**2. 10** **mm Dia steel Nos = 120**, Unit Weight of **10 mm Dia Steel = 0.620 kg/m**

**Total Weight **of **8 mm** dia steel = Nos x Unit Wt x Length of Steel (12 m)

= 80×0.620×12

**= 892.8 kg**

**3. 12 mm Dia steel Nos = 50, Unit Weight of 12 mm Dia Steel = 0.890 kg/m**

Total Weight of 12 mm dia steel = Nos x Unit Wt x Length of Steel (12 m)

= 80×0.89×12

**= 534 kg**

**4. 16 mm Dia steel Nos = 60, Unit Weight of 16 mm Dia Steel = 1.58 kg/m**

**Total Weight **of **8 mm **dia steel = Nos x Unit Wt x Length of Steel (12 m)

= 80×1.58×12

**= 1137.6 kg**

**20 mm** Dia steel **Nos = 30**, Unit Weight of **20 mm** Dia Steel = **2.46 kg/m**

To**tal Weight** of **20 mm** dia steel = Nos x Unit Wt x Length of Steel (12 m)

= 80×2.46×12

**= 885.2 kg**

## FAQs:

### Unit Weight of Steel

The unit weight** of steel** is around **7850 kg/m3** or 7.85 g/cm3 or** 490 lbs/ft3** or **13231 lbs/yd3**. The steel bars are **majorly **used as **reinforcement** to strengthen the **tensile property** of concrete **structures.** The **steel weig**ht is generally measured in** Kg**, **Ton**, and **pound.**

### Weight of Steel Bars Formula

The **formula** used to calculate the **unit weight of steel bars** is **D²/162**. Where, **D = Dia. Of steel **bars, **162 i**s a **constant value.**

### Weight Formula for Steel

The **formula** used to calculate the **unit weight of steel bars** is **D²/162**. Where, **D = Dia. Of steel **bars, **162 i**s a **constant value.**

### Unit Weights of Steel

The unit weight** of steel** is around **7850 kg/m3** or 7.85 g/cm3 or** 490 lbs/ft3** or **13231 lbs/yd3**. The steel bars are **majorly **used as **reinforcement** to strengthen the **tensile property** of concrete **structures.** The **steel weig**ht is generally measured in** Kg**, **Ton**, and **pound.**

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