Concrete is a valuable material in all sorts of construction projects, mainly where highly compressive strength is necessary. Before calculating, you must understand the concept of direct estimation.
There is a straight forward formula to calculate the amount of concrete for walls, slabs, columns, and many more, but you need to check the volume.
Determining the amount of cement bags are necessary for the job and so learn how to evaluate appropriately.
Enter the depth, width and length of your concrete slab to calculate the number of cubic yards and concrete bags needed to complete your project..
Enter the depth, width and length of your concrete footing to calculate the number of cubic yards and concrete bags needed to complete your project.
Enter the diameter and height of your concrete column to calculate the number of cubic yards and concrete bags needed to complete your project.
Use Our free calculator to find out how much concrete you need for your construction project. Our tool will help you to calculate the concrete yardage and the number cement bags by size.
Formula To Find Out Volume Of Concrete
We all are aware of the volume and its simple formula. So, we need to know the volume of concrete, which will tell us how much concrete you need. For instance, take a box and fill it with cement. Then what will be the volume of the concrete in the box? It is simple –
Volume of the concrete box = length * width * Height
Suppose the box have 1 meter length, 2 meter height, and 1 meter width, then –
Volume = 1 * 2 * 1 = 2 cubic meter.
Hence, for filling the one cubic meter of the box, you need 25 KN of concrete where 1 KN = 100 kgs)
So, for filling two cubic meters, you need a 2 * 25 = 50 KN mixture of cement. It means volume or amount of concrete is the evaluation of a 3D object.
The formula varies according to the shape. But the method remains the same for calculating the volume of any of the figures. It is the multiplication of three dimensions.
For instance, take the cylinder that neither has length nor breadth. For calculating the cylinder, you need to multiply the area of a circle by the height of the cylinder. It is –
Volume of cylinder = Depth/height * Surface Area
After evaluating volume, what to do to find out the amount of cement? Let us see –
Simple Steps That Every Concrete Calculator Use
Below are simple and easy steps to evaluate the amount of cement mixture for any shape –
- Check out how much thickness you want
- Measure the width and length of the space that you want to cover.
- Evaluate the product of length and width for identifying the square foot
- Now convert the thickness from inches to feet
- Calculate the product of thickness (in feet) and square foot for cubic feet result.
- Then convert cubic feet to cubic yards by multiplying with 0.037.
For determining the number of concrete bags you need, divide the overall cubic yards by yield. You can utilize the following yields according to the size of one bag –
- 40 pounds bag yield has 0.011 cubic yards
- A 60-pound bag can cover 0.017 cubic yards
- The 80-pound bag can yield 0.022 cubic yards
So, Below is a brief discussion regarding the amount of concrete you need for footings, walls, slabs, etc.
Calculate Amount For Footings
Footing is the exterior wall of the building, which disperses the weight over the wide area. It is helpful to prevent settling. There are two primary types of footings like spot footings and continuous spread footings.
Spot footings are where the posts of the pier or building sit, and continuous spread footings are where the frame of the building sits on. The foremost thing you have to do is check out the type of footing you need to pour.
Concrete Calculation Formula For Spot Footing
Follow the below steps –
Spot footing is usually about 2 by 2 square, which is around 10 to 12″ deep. It means the length is 2′, width is 2′, and height/depth is 12″.
So, you have to convert all measurements into feet by dividing the depth/height by 12″.
12″/12″ =1 foot
Secondly, you have to multiply all dimensions for evaluating the cubic feet of cement mixture you require.
Volume = L * W * H/D = 2′ * 2′ * 1′ = 4 cubic feet
Find out the product of the number of posts you need to support with spot footing. For instance, a pier supports eight posts 4′ * 8 = 32 cubic feet.
Concrete is available in cubic yards. However, our calculated measurement is in cubic feet, so you need to convert it into cubic yards. Multiply your cubic feet result by 0.037037037.
It results –
32 cubic feet * 0.37037=1.185185 184 cubic yards.
Hence, cement helpful for this type of footing ranges in between 3000 and 5000 PSI in compression.
Concrete Calculation For Continuous Spread Footing
Follow the below steps –
Continuous spread footing is generally about 16 inches to 24 inches wide with a depth of about 6 inches to 16 inches deep. So building dimensions are 24′ by 32′, which means we need to find out the perimeter for the length. Length is 24′ + 32′ + 24′ + 32 = 112′; width = 24′ and depth = 16′.
Now convert all measurements into feet the same as above by dividing the width and depth by 12″.
24″/12″ = 2 feet and 16″/12″ = 1.33 feet
Multiply all dimensions for determining the cubic feet you require. 112′ * 2′ * 1.33′ = 297.92 cubic feet.
As we already know, concrete is available in cubic yards, so let us convert cubic feet into cubic yards multiplying it by 0.37037037.
297.92 cubic feet * 0.37037037 = 11.03407406 cubic yards. Cement in this type of footing ranges from 2000 to 5000 PSI in compression.
Grade Beam Footing Evaluation
The third and less frequently advantageous footing is the grade beam footing which is usually the sum of continuous spread footing and spot footing.
To calculate grade beam footing, evaluate continuous spread footing first followed by spot footing and add cubic yards altogether to determine the amount needed for this sort of footing.
Calculation Of Cement For Column
There is an online concrete calculator for columns, footing, walls, etc., that can be helpful for you to find out the volume and weight of the concrete you require for your project. However, you need to follow few steps before that, and you can also calculate it manually like –
Columns are of any shape, such as rectangular or circular. But remember,
Volume = surface area * depth
Rectangle Column Shape
Understanding it with the example. Suppose your rectangular column has length = 0.6m, breadth = 0.4m and height is 3m. For calculating the top surface area and get the product of it with depth/height.
Volume Required For Rectangular column = 0.6 * 0.4 * 3= 0.72 cubic meter
Circular Column Shape
Suppose the circle’s radius is 0.25 m, then the volume of the circle column is the product of the surface area of the circle and the height of the column.
Volume of circle column = Pie * (square of radius) *3 = 3.14 * 0.25 * 0.25 * 3 = 0.58 cubic meter.
Concrete Evaluation For Slabs
The slab is available in the shape of a rectangle. So for evaluating the volume needed for the slab, please find out the surface area and multiply it by the thickness/depth of the slab. Suppose the rectangles measurements are –
Length = 6 m; breath = 5m; depth/thickness = 0.15m
Volume = Area of rectangular slab * depth/height
Evaluate the area of rectangle with its measurements (length and width) –
Area = length * width = 6 * 5 = 30 square meter
Find out The volume of the concrete. V = LBH
Volume of concrete needed = 30 square meter * 0.15 = 4.5 cubic meter
Convert 4.5 cubic meters into cubic yards. One cubic meter = 1.30795 cubic yards. So,
4.5 cubic meters * 1.30795 = 5.88578 cubic yards.
Concrete For Wall Calculation
For the wall made up of concrete, the calculation is almost the same – height * length * width. Suppose the volume in cubic meters for the wall has a height of 2m, width of 20 cm, and length of about 4m.
Volume of concrete needed = 2 * 4 * 0.2= 1.6 cubic meters. You will then convert it into cubic yards, and you will get the concrete amount you need for a wall.
Concrete Calculations For Curb, Staircase, and Gutter
More complex forms like a gutter, staircase, and curb utilize the same approach, but the calculation is complicated. So you need a calculator for it. For the gutter and curb, it is the situation to combine the volume of curb and gutter using the below formula –
Curb depth * (height of curb + thickness of flag) * length + width of gutter * thickness of flag *length
The staircase is the most complex one because we need to account for the rising volume of concrete for every subsequent stair.
We need to evaluate volume for n number of steps. Suppose n = step 2 having a raise of 6 inches, length of 6 inches, and width of 4 feet, convert inches into feet. Six inches will be 0.5 feet. So, calculation will be n*l*w*h = 2 * 0.5 * 0.5 * 4 = 2 cubic feet. Convert it into cubic yards.
The in-depth discussion of concrete calculation is given above in the article. Read it and determine how much concrete you require for your footings, slab, wall, flooring, and so on.