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Rebar Calculator

Rebar Calculator

Enter the length and width of the grid and the calculator will calculate the number of rebars, rebar length, and cost required to build up the rebar grid.





Rebar-rebar (grid):




Wire Price:



Length of a single rebar:



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The online Concrete Rebar calculations assists civil engineers how much Rebar for a concrete slab required. The Rebar calculator for slab help to estimate the dimension of the grid that should be used

In this topic, we find how to calculate Rebar for your project, so you can protect your assets.

Why do we use Rebar?

The most important characteristic of the Rebar and to expand along with the thermal expansion of the steel bars. This is the main reason the Rebar increases the strength of the concrete slab footings.The Rebar for footings best to find the Rebar for slab footing. There are specific calculations taken into account when installing the Rebars in the concrete Rebar slab. It is best to use the efficient Rebar slab calculator to find the value of the Rebar.
Why do we Use Rebar?

We can find the value of a concrete slab through a concrete slab Rebar efficiently.

How much Rebar do I need?

The Rebar is measured in Imperial bar and also in the metric bar size. The value of a concrete slab can be measured by a concrete slab Rebar efficiently in a matter of a couple of seconds. The nominal diameter of Rebar in the Imperial Units and the Metric system is represented in the table below:

Imperial bar size Nominal diameter (in) Metric bar size (soft) Nominal diameter (mm)
#2 0.250 = 1⁄4 No.6 6.35
#3 0.375 = ​3⁄8 No.10 9.525
#4 0.500 = ​1⁄2 No.13 12.7
#5 0.625 = ​5⁄8 No.16 15.875
#6 0.750 = ​3⁄4 No.19 19.05
#7 0.875 = ​7⁄8 No.22 22.225
#8 1.000 = ​8⁄8 No.25 25.4
#9 1.128 ≈ ​9⁄8 No.29 28.65
#10 1.270 ≈ ​10⁄8 No.32 32.26
#11 1.410 ≈ ​11⁄8 No.36 35.81
#14 1.693 ≈ ​14⁄8 No.43 43
#18 2.257 ≈ ​18⁄8 No.57 57.3

The Rebar you need should be calibrated precisely and the Rebar weight calculator can make your measurement precise.

How to find the Rebar?

You don’t need to worry about the Rebar calculations. We can find the value of a concrete slab by a concrete slab Rebar efficiently. You can calculate Rebar needed for a slab if you are able to understand the terms given below:

Rebar grid length:

The concrete rebar calculations can’t be done without knowing its dimension, especially the length and width. The formulas for the Rebar grid dimension and also for the are given below:

Grid length = Slab-length – (2 * edge-Rebar-spacing)

The total length needed for Rebar is measured vertically and horizontally. This is essential to know how much Rebar for the concrete slab is required. Rebar spacing calculator is perfect to indicate how much Rebar is needed.

You can use the concrete Rebar calculations to find the amount of Rebar for each slab. For this purpose, the number of rows is measured by dividing the grid length and by the Rebar spacing to obtain the length of the grid width. The rebar weight calculator is a good way to find the weight of the Raber in total.

total rebars length = (rebar-columns * rebar-length) + (rebar-rows * rebar-width)

The number of the Rebar pieces:

The Rebar pieces can be calculated by dividing the total Rebar length divided by a single Rebar length.

rebar pieces = total-rebars-length / single-rebar-length

Total cost of Rebar:

Multiply the number of total Rebar pieces by the price of one piece, which we have calculated before:

The cost of the Rebar=total cost (unit cost/unit length)

How to find the cost of Rebar?

The Rebar cost can be calculated by the length and the width of the Raber, then specify the spacing of the Rebar. The filling price of single Rebar should be calculated and that is the price of the Rebar you are buying from the supplier. The Rebar cost calculator is a great online source to find the Rebar cost.

Practical Example:

The total length of the Rebar is 840 feet, the unit length is 20 feet and the unit price is $5.63.Use the Raber estimator to estimate the Raber.
The cost of the Rebar=total cost (unit cost/unit length)
The cost of the Rebar=840 (5.36/20)

The cost of the Rebar=$236.46 

We can use the Rebar cost calculator to find the total cost of the Rebar.

Advantages of using Rebar:

There are multiple benefits of the Rebar for construction sites:

  • Rebar increases the tension resistance of the concrete.
  • The cracking resilience of the concrete also improved due to Rebar.
  • Rebar allows us to reduce the thickness of the concrete block.

Working on the Rebar Calculator:

The Rebar slab calculator is efficient to calculate the Rebar values:


  • Enter the length, width, and grid of Rebar
  • Enter the edge grid, wire price, and Length of a single rebar


The following output data display: 

  • Grid length 
  • Grid Width
  • Price of a single Rebar 
  • Total Rebars length


How do you calculate how much rebar is needed?

First, you need to determine the Rebar needed for the footing. The Rebar calculator for footings is handy to find the Rebar for slab footing. The common estimation of the Rebar per 8 inches of the footing width. If you stick to this calculation for 16 inches rebar you need 2 Rebars and so on for 24,32 inches wide footing width. For a quick estimation, you may need to use the online tool, the concrete Rebar calculations renowned to find the Rebar estimation for the footing width. 

How far apart should the rebar be placed?

Work out the rebar spacing by using the rebar spacing chart. You also need to use manufacturer literature for maximum and other support spacing. The appropriate rebar spacing for most of the slabbing is 12-inches.To find the exact size of the slab by slab Rebar calculator.

What should be the size rebar for a 4-inch slab?

For a 4-inch slab, the thickness of the rebar should be ⅛ of the slab. The Rebar calculator for slab is best to find the Rebar size.

Do you require gravel under concrete?

You need gravel under a concrete slab, footing, or patio. The beneficial thing about gravel is, that it provides the foundation for your concrete. The gravel is usually used to improve the drainage, preventing the water from pooling. The concrete Rebar calculations can be used to find the grave required.

What is the main difference between the number 3 and the number 4 rebar?

The main difference between the number 3 and the number 4 rebar is the minimum yield strength. The minimum yield strength for the number 3 rebar is 6,600 lbs, whereas the number 4 rebar’s minimum yield strength is 11,780 lbs. The yield strength for the number 4 rebar is greater than 78% than the number 3 rebar. A slab Rebar calculator can test the minimum yield strength for rebar.


The Rebar is reinforcement steel used to improve the properties of the concrete blocks. The Rebar wires are prepared with patterned steel and improve adhesion. These Rebar wires are placed in a way to create a mesh. As the Rebar wires are made of specially crafted steel, it increases the life of the concrete slabs. 


From the source of Wikipedia: Rebar, Use in concrete and masonry
From the source of Wikipedia: Stainless Steel Reinforcement, Why is stainless steel reinforcement superior?