CalCon’s concrete calculator will be beneficial in estimating the amount of concrete you want to cover a specific area. If you want to know how many bags of concrete or the density of concrete, our calculator will help you with that as well. All other information related to the process of making concrete and how to use our calculator, find out below.

Also, see our other concrete related calculators, such as Concrete Estimator Tube and Concrete Weight Calculator.

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Concrete definition

Back in 1824, Joseph Aspdin came up with the idea and made a mixture that was a combination of limestone and clay. Nowadays, in construction, you can use a mix of aggregate particles, cement, and water that is concrete. This is undoubtedly one of the most commonly used materials in the world. The intensity of concrete strength directly depends on the weather conditions, especially the temperature and humidity.

You can measure it in kilograms per square centimeter. The durability of concrete is also affected by the amount of cement to the number of aggregate particles used. If you need the more substantial, you will use fewer aggregate particles, whether gravel, sand or crushed stone. The production of concrete is more advanced. In practice, there are different types of concrete you can use to construct residential buildings and other types of buildings.

Why use the concrete calculator?

You have probably found yourself in a situation where you have decided to build an object yourself. It does not matter whether it is a house or something more straightforward. After a previously prepared list of all the necessary ingredients, it is essential to know what quantities do you need. When calculating the exact number of concrete bags for forming concrete slabs of different shapes, our calculator provides you with great help. Following all the instructions and entering all the necessary values you have imagined according to the project design. The calculator will provide you with all the values. 

How much concrete do I need?

It is necessary to follow the steps that we will explain below.

  1. Estimate the required amount of concrete. Indicating the values of length, width, and height, and the number of concrete slabs or surfaces you want to coat with concrete.
  2. Determine the weight of the listed elements. More precisely, the number of concrete bags that you buy in shops equipped with construction materials.
  3. Do not forget to indicate the value of the ratio of waste that may occur due to improper spillage, malfunction of purchased elements, or other potential events.

An example calculation

In the following example, we will clarify the calculation using our calculator.

We will imagine that you need 4 concrete elements, 4 feet high, 4 feet long, and 4 feet wide. With such default values, you can cover an area of 64 square meters with a volume of 256 cubic feet. After the measurements, it is necessary to check the density of the concrete you bought, which you can change if necessary.

If we put that in this example, the density of concrete is 130 pounds per cubic feet, and the weight of a concrete bag is 60 lb. In conclusion, you need 555 bags to cover the whole space. It is necessary to add to this calculation the value of waste material that can occur due to the negligence of workers or other cases, which can be from 5-10%. After that, the result that the calculator will show you is that you need 582 bags of cement to cover the space.

Concrete slab cost

One of the most critical structural elements of any construction project is the concrete slab. They come in horizontal shapes in order to form a flat surface. You have started a project, but you do not know precisely how many concrete slabs you need. CalCon’s concrete calculator can make it much easier for you to calculate the cost of a single concrete slab. You need to know the data on the exact amount of concrete, the precise amount of concrete bags, and how many slabs you can produce with that amount of concrete. Then, it is enough to enter all the data in the places provided in our calculator. After that, the calculator will show the cost of one concrete slab, paving the selected space, and the total material cost needed for concrete.

Concrete slab
Concrete slab

How to make concrete?

The concrete production process is very demanding and time-consuming. When mixing concrete, it is necessary to know the correct water and cement ratio. It is required to put the right amount of water to surround each aggregate particle (sand, gravel, crushed stone) with cement. The less water you use in the mixture, the stronger the concrete, and vice versa. This process of connecting water with cement and aggregate particles is called hydration. The results is a solid mixture ready for further use.

In addition to the listed ingredients of concrete, there are other types of additives in the form of superplasticizers that you can use. After the mixing process, you need to pour the concrete into the intended place before it hardens. To achieve sufficiently strong, long-lasting, and durable concrete, the correct ratio of all the ingredients needed to form the concrete direction is crucial. Failure to match all ingredients will result in the cracking of the concrete. You can generally pack and transport concrete in bags that can deliver large quantities of concrete.

Elements of concrete
Elements of concrete

Concrete vs. cement

The main reason why many are confused about the terms cement and concrete is that cement is an integral element of concrete. When in contact with water, cement forms a paste that forms concrete by mixing with aggregate particles. Cement as a building material is rich in calcium and silicon. Due to its sticky properties, it is ideal as a binder. If you use it alone, it can lead to cracking. Cement is not long-lasting, while concrete can last for hundreds of years after pouring. When it comes to more complex construction projects, concrete is something you can’t imagine the construction process without, while you can use cement if you need to make certain repairs. The name Portland cement is a term used for all types of cement that you can use to form concrete.

Difference between concrete and cement
Difference between concrete and cement

Types of concrete

Concrete production depends on the needs of the construction project. Accordingly, we distinguish different types of concrete that differ in the ratio of elements, hardness, and other factors, all to meet the needs of a broad market. Some of the best-known types of concrete are: ordinary concrete, lightweight concrete, reinforced concrete, high-density concrete, prestressed and precast concrete, asphalt, aerated concrete, fiberglass concrete, pumped and vacuum concrete, porous concrete, sprayed concrete, ready-mix concrete, or intelligent concrete.

Different types of concrete
Different types of concrete

Example 1 – Calculate concrete volume with steps

Staircases are one of the crucial parts of any building. It helps people access and move between floors and other rooms in the building. To know how much concrete is needed to form stairs, you need to know the stairs’ rise, run, platform depth, and width.

We will take, for example, that the width is 3 feet, the run is 0.5 feet, the rise is 0.7 feet, and the platform depth is 4 feet. The number of steps contained in this staircase is 12. With all the default data for concrete density of 150 lb / cu ft and weight of one bag of 60 lb, we get that 447 concrete bags are needed to concrete a staircase of these dimensions. 

Example 2 – Calculate concrete volume of a wall

In this example, you need to know the values of the three elements: height, width, and depth. Also, you can use our calculator, which can help you with calculations. You need to enter data. The length is 3 feet, the wall width is 2 feet, and the wall depth is 0.5 feet. Because you have 5 walls of this size, the total volume is 15 cubic feet. You can get this by multiplying all the values by the number of walls:

3\cdot 2\cdot 0.5\cdot 5 = 15


How to calculate how much concrete I need?

It is enough to follow these steps to calculate the required amount of concrete. First, you need to determine the thickness of the concrete, along with the dimensions of the space you want to cover. The dimensions of the length need to be multiplied by the width to get the exact square footage of the space. Then multiply the thickness of the concrete by the obtained square footage to get the total amount that needs to be covered.

  • How much concrete do I need for a 10×10 slab?
  • If you have a concrete slab measuring 10×10, you need 1.23 cubic meters of concrete, 4 inches thick. If the slab is denser, it will require more concrete.

  • How much does a 100lb bag of concrete cover?
  • For a concrete slab of standard dimensions, 10 feet x10 feet, 4 inches thick, 50 100lb bags you require.

  • How much cement do I need for a 12×12 slab?
  • If you have a concrete slab measuring 12×12, 4 inches thick, in that case, you will need 1.76 cubic meters of concrete, which in translation would mean about 104 bags weighing 60lb.