Whether you’re planning to install reinforcement on your project or are estimating the total quantity of reinforced required; you need to know the weight of rebar per foot or weight of rebar per linear foot.

The rebar weight depends on the length as well as the diameter of rebar. So, that’s why a 20 foot piece of #4 rebar weight will be different as compared with the #8 rebar weight per foot.

The most common size of rebar normally used in residential buildings is half-inch rebar while for commercial projects, you may need to use higher number of rebar including #8, #10, and even #11. Diameter of rebar more than #11 are very rarely used and are not that common.

Also Read: How much does #8 rebar weight per foot [SOLVED]

So, in our today’s post we’ll discuss how to calculate weight of steel bars in feet.

Unit weight of rebar

 By unit weight we mean the weight of rebar per linear feet or per meter. The unit weight is mostly used while estimating the total bar weight requirements in bar bending schedule. Here’s the typical process for bar bending schedule:

• The estimator takeoff the requirement of bars and identify the different types keeping in view the shape and the diameter.
• For different shapes and diameter, they give a special identification number that makes identification easy.
• For each cut piece, they calculate the total length and number of pieces required as per the plan and section of reinforcement.
• At the end, for each diameter, the total length is converted to total weight by multiplying the length with the unit weight of rebar.

Rebar Unit Weight:

U. S	S. I	Kg/m	lb/ft
3	#10	0.56	0.38
4	#13	1.00	0.67
5	#16	1.56	1.04
6	#19	2.24	1.50
7	#22	3.05	2.04
8	#25	3.98	2.67
9	#29	5.07	3.40
10	#32	6.42	4.30
11	#36	7.92	5.31
12	#38	8.93	5.99
14	#43	11.41	7.65
16	#50	15.88	10.65
18	#57	20.28	13.60
20	#64	24.82	16.63

US Imperial System rebar size table

US or Imperial system designates rebar as Number or (#) so for we’ll write as “#4” rebar and say it as Number 4 rebar. This system number gives diameter in units of 1/8 inch or 3.2 mm. So, the diameter of #4 rebar will be 4 x 1/8 inch or 4 x 3.2 mm that’s equal 0.5 inches or 12.8 mm.

Let’s first see the diameter size of various rebar on the basis of US Imperial System:

Size of #2.5 rebar/ reinforcing bar

In US or Imperial system we’ll write as “#2.5” rebar and say it as Number 2.5 rebar. This system number gives diameter in units of 1/8 inch or 3.2 mm. So, the diameter of #2.5 rebar will be 2.5 x 1/8 inch or 2.5 x 3.2 mm that’s equal 0.3125 inches or 8 mm.

Size of #3 rebar/ reinforcing bar

In US or Imperial system we’ll write as “#3” rebar and say it as Number 3 rebar. This system number gives diameter in units of 1/8 inch or 3.2 mm. So, the diameter of #3 rebar will be 3 x 1/8 inch or 3 x 3.2 mm that’s equal 0.375 inches or 9.6 mm.

Size of #4 rebar/ reinforcing bar

In US or Imperial system we’ll write as “#4” rebar and say it as Number 4 rebar. This system number gives diameter in units of 1/8 inch or 3.2 mm. So, the diameter of #4 rebar will be 4 x 1/8 inch or 4 x 3.2 mm that’s equal 0.5 inches or 12.8 mm.

Size of #6 rebar/ reinforcing bar

In US or Imperial system we’ll write as “#6” rebar and say it as Number 6 rebar. This system number gives diameter in units of 1/8 inch or 3.2 mm. So, the diameter of #6 rebar will be 6 x 1/8 inch or 6  x 3.2 mm that’s equal 0.75 inches or 19.2 mm.

Size of #7 rebar/ reinforcing bar

In US or Imperial system we’ll write as “#7” rebar and say it as Number 7 rebar. This system number gives diameter in units of 1/8 inch or 3.2 mm. So, the diameter of #7 rebar will be 7 x 1/8 inch or 7  x 3.2 mm that’s equal 0.875 inches or 22.4 mm.

Size of #8 rebar/ reinforcing bar

In US or Imperial system we’ll write as “#8” rebar and say it as Number 8 rebar. This system number gives diameter in units of 1/8 inch or 3.2 mm. So, the diameter of #8 rebar will be 8 x 1/8 inch or 8  x 3.2 mm that’s equal 1 inches or 25.4 mm.

Size of #9 rebar/ reinforcing bar

In US or Imperial system we’ll write as “#9” rebar and say it as Number 9  rebar. This system number gives diameter in units of 1/8 inch or 3.2 mm. So, the diameter of #9 rebar will be 9 x 1/8 inch or 9  x 3.2 mm that’s equal 1.125 inches or 28.8 mm.

Size of #10 rebar/ reinforcing bar

In US or Imperial system we’ll write as “#10” rebar and say it as Number 10 rebar. This system number gives diameter in units of 1/8 inch or 3.2 mm. So, the diameter of #10 rebar will be 10 x 1/8 inch or 10  x 3.2 mm that’s equal 1.25 inches or 32 mm.

Size of #11 rebar/ reinforcing bar

In US or Imperial system we’ll write as “#11” rebar and say it as Number 11 rebar. This system number gives diameter in units of 1/8 inch or 3.2 mm. So, the diameter of #11 rebar will be 11 x 1/8 inch or 11 x 3.2 mm that’s equal 1.375 inches or 35.2 mm.

Rebar Weight Calculation Formula:

By using the formula d²/162 we can easily calculate the unit weight of any steel rebar and it will give us weight in kg per meter.

So, if we have the weight in kg per meter of a bar, we can simply multiply it by the length of a bar to find out the total weight of a bar.

Similarly, if we want to find out the weight in kg per foot of a bar all we need to do is use d²/533 formula.

This is very helpful when calculating the number of rebars required to complete a project.

Rebar weight per foot

The rebar weight per foot for different rebar varies from 0.265 lbs to 4.303 lbs. #2.5 reinforcing bar has a weight per foot of 0.265 lbs per foot, #3 rebar has 0.376 pounds per foot, #4 rebar has 0.668 pounds per foot, #5 rebar has 1.043 pounds per foot, #6 rebar has 1.502 pounds per foot, #7 rebar has 2.044 pounds per foot, #8 rebar has 2.670 pounds per foot, #9 rebar has 3.40 pounds per foot, while #10 rebar has 4.303 pounds per foot.

If you know the diameter of rebar, you can calculate the weight in kg/foot using following formula:

                Unit weight (kg/foot) = D*D / 533 (kg/foot)

We’ll now use this formula to calculate rebar weight per foot of various diameters.

Weight of #2.5 rebar per foot

Rebar with diameter of #2.5 or 8 mm reinforcing bar has a weight per foot of 0.265 pounds which is approximately equal to 0.12 kg/foot.  You can calculate the weight by using formular D2 / 533 as 8×8/533 = 0.12 kg/foot.

Weight of #3 rebar per foot

Rebar with diameter of #3 or 10 mm reinforcing bar has a weight per foot of 0.376 pounds which is approximately equal to 0.1876 kg/foot.  You can calculate the weight by using formula D2 / 533 as 10×10/533 = 0.1876 kg/foot.

Weight of #4 rebar per foot

Rebar with diameter of #4 or 12 mm reinforcing bar has a weight per foot of 0.668 pounds which is approximately equal to 0.270 kg/foot.  You can calculate the weight by using formula D2 / 533 as 12×12/533 = 0.270 kg/foot.

Weight of #5 rebar per foot

Rebar with diameter of #5 or 16 mm reinforcing bar has a weight per foot of 1.043 pounds which is approximately equal to 0.48 kg/foot.  You can calculate the weight by using formula D2 / 533 as 16×16/533 = 0.48 kg/foot.

Weight of #6 rebar per foot

Rebar with diameter of #6 or 20 mm reinforcing bar has a weight per foot of 1.502 pounds which is approximately equal to 0.75 kg/foot.  You can calculate the weight by using formula D2 / 533 as 20×20/533 = 0.75 kg/foot.

Weight of #7 rebar per foot

Rebar with diameter of #7 or 22 mm reinforcing bar has a weight per foot of 0.908 pounds which is approximately equal to 0.75 kg/foot.  You can calculate the weight by using formula D2 / 533 as 22×22/533 = 2.044 kg/foot.

Weight of #8 rebar per foot

Rebar with diameter of #8 or 25 mm reinforcing bar has a weight per foot of 2.670 pounds which is approximately equal to 1.173 kg/foot.  You can calculate the weight by using formula D2 / 533 as 25×25/533 = 1.173 kg/foot.

Also Read: Composite Rebar – Carbon Fiber Rebar (CFRP) Benefits & Costs

Weight of #9 rebar per foot

Rebar with diameter of #9 or 22 mm reinforcing bar has a weight per foot of 3.40 pounds which is approximately equal to 1.47 kg/foot.  You can calculate the weight by using formula D2 / 533 as 28×28/533 = 1.47 kg/foot.

Weight of #10 rebar per foot

Rebar with diameter of #10 or 22 mm reinforcing bar has a weight per foot of 3.40 pounds which is approximately equal to 1.47 kg/foot.  You can calculate the weight by using formula D2 / 533 as 22×22/533 = 1.47 kg/foot.

Rebar weight per meter

If you know the diameter of rebar, you can calculate the weight in kg/meter using following formula:

                Unit weight (kg/meter) = D*D / 162 (kg/meter)

We’ll now use this formula to calculate rebar weight per meter of various diameters.

For 6mm Diameter bar:

Diameter of bar = 6mm

Bar weight = 1 m

Unit weight of 6 mm diameter bar

= D²/162

= 6²/162

=36/162

= 0.222 kg/m    (unit weight of 6mm bar is 0.222 kg/m)

For 8mm Diameter bar:

Diameter of bar = 8mm

Bar weight = 1 m

Unit weight of 8 mm diameter bar

= D2/162

= 8²/162

=64/162

=0.395 kg/m    (unit weight of 8mm bar is 0.395 kg/m)

For 10mm Diameter bar:

Diameter of bar = 10mm

Bar weight = 1 m

Unit weight of 10 mm diameter bar

= D2/162

= 10²/162

=100/162

=0.617 kg/m   (unit weight of 10mm bar is 0.617 kg/m)

For 12mm Diameter bar:

Diameter of bar = 12mm

Bar weight = 1 m

Unit weight of 12 mm diameter bar

= D2/162

= 12²/162

=144/162

=0.890 kg/m   (unit weight of 12mm bar is 0.890 kg/m)

For 16mm Diameter bar:

Diameter of bar = 16mm

Bar weight = 1 m

Unit weight of 16 mm diameter bar

= D2/162

= 16²/162

=256/162

=1.58 kg/m   (unit weight of 16mm bar is 1.58 kg/m)

For 20mm Diameter bar:

Diameter of bar = 20mm

Bar weight = 1 m

Unit weight of 20 mm diameter bar

= D2/162

= 20²/162

=400/162

=2.46 kg/m   (unit weight of 12mm bar is 2.46 kg/m)

For 25mm Diameter bar:

Diameter of bar = 25mm

Bar weight = 1 m

Unit weight of 25 mm diameter bar

= D2/162

= 25²/162

=625/162

=3.85 kg/m   (unit weight of 12mm bar is 3.85 kg/m)

For 32mm Diameter bar:

Diameter of bar = 32mm

Bar weight = 1 m

Unit weight of 32 mm diameter bar

= D2/162

= 32²/162

=1024/162

=6.32 kg/m   (unit weight of 12mm bar is 6.32  kg/m)

For 40mm Diameter bar:

Diameter of bar = 40mm

Bar weight = 1 m

Unit weight of 40 mm diameter bar

= D2/162

= 40²/162

=1600/162

=9.87 kg/m   (unit weight of 12mm bar is 9.87kg/m)

Reinforcement – the Introduction

Reinforcement bars or rebars is a bar of steel that is used to reinforce and strengthen concrete under tension and compression. Rebar helps making concrete less brittle and as a result the concrete elements are able to give warning before failure.  

There are different steel rebar sizes, grades, and types to support a variety of massive structures like bridges, dams, and tunnels. There is a variety of rebar lengths and diameters available, metric size and imperial size are the two most popular measurements.

Rebar Grades:

Rebar grades are set by the American standard for Testing and Material commonly known as ASTM. Rebar grade is the maximum yielding strength and tensile strength of the bar.

The yielding strength is the minimum weight-bearing capacity of any bar.  If the weight exceeds its yielding strength, then the rebar would permanently deform and it will go into a plasticity state. Whereas, tensile strength is the maximum amount of stress a material can take before being permanently damaged or broken.

 Normally, in high-rise structures grade 60 is used. We can identify the grade of any rebar just by seeing it.

How is that even possible? Right, well there is no need to worry, anybody can tell the grade of the rebar. In the manufacturing process of steel, grade 60 steel is given yellow color at the cut face whereas grade 40 is given red color.

So next time you see a truck loaded with rebars, you will know what grade of steel he is carrying. Common steel grades used in the construction industry are grade 40, grade 60, grade 75, grade 80, and grade 100 rebar.

Types of Rebars:

The selection of suitable rebar for different types of construction projects is very important as it can alone do some irretrievable damage. Some of the common types of rebars are as follows:

• Carbon Steel Rebars
• Stainless Steel Rebars
• Galvanized Rebars
• Glass Fiber Reinforced Polymer (GFRP) Rebars
• Epoxy coated Rebars
• Welded Wire Fabric (WWF) Rebars
• Expanded Metal Rebars

In day-to-day construction, plain carbon steel or cast iron is extensively used to carry out massive structures.

Also Read: Rebar – Types of Rebar in Construction – Grades & Sizes – Properties [PDF]

The biggest benefit of plain carbon steel is its durability, and it is strong as well as anti-shock. Plain carbon steel is relatively soft yet strong, carbon steel is difficult to work as rebar grade increases. It has its own properties, as it can be welded in a room-temperature environment.

Rebars are often deformed with ribs to promote a better bonding with concrete material and reduce the risk of slippage. These rebars are used in many masonry and concrete projects to reinforce slabs and structures.

In columns and beams, they are deformed to make stirrups to hold the main dowl bars of columns and beams. Rebar weight can be obtained from the relevant ASTM standards.

Also Read: Types of Rebar Support and Chair Spacing (Made EASY)

The manual calculation of the rebar weight per foot or rebar weight per meter could be a little difficult from the values specified in the standards. It is very important to be apprehensive of the rebar unit weight as there are limitations of variations. As per code-specified tolerances shall be allowed to be changed.