What is a Concrete Block Calculator and Why is it Used in Construction?

A concrete block calculator is an online tool that helps you calculate the number of concrete blocks you need for your project. The calculator is mostly used by contractors and builders to provide a quote to their customers. The concrete block calculator can be accessed from anywhere with the help of internet access. The result given by it is considered to be 99 percent accurate. It shows the accurately estimated blocks required based on the data you provide it. Meanwhile, we can say that it works similarly to other calculators, where we provide the data for calculation and the calculator applies the formula to give us the answer. So, before moving further to understand the calculator, you must know a bit about concrete blocks, what they actually are, and where they are used in construction.

Concrete Block

Concrete blocks are one of the important materials in construction. Concrete blocks are building units made from concrete. They are rectangular-shaped. If we talk about its size, it usually varies due to its type and the project’s needs. Basically, we can say that these blocks are ready-made pieces of concrete which are ready to use at the site. It can also be known as a large brick type that builders place one over another with mortar to create walls and other structures. In short, we can say it is a similar version of the bricks but made of concrete. The main difference between using these blocks and bricks is the strength, size, and durability. Bricks are shorter in size, less durable, and require sufficient time to get placed anywhere. On the other hand, a concrete block is bigger and stronger. It is prepared to carry heavy loads and last for many years. Concrete blocks are very common in construction all over the world because of their strength and their easy-to-use properties. Concrete blocks are used in many parts of construction because they are strong and easy to install. The most common place you see them is in walls. Builders use them for both internal walls and external walls. They are also used in foundations to give strength to the building structure. These are further of two types, solid or hollow. Solid blocks are placed under buildings to carry the load of the structure. Hollow blocks are often chosen for tall walls because they reduce the overall weight by providing full strength.

Usage of the Calculator

A concrete block calculator is mainly used to find out how many blocks you need for a building, a wall or any construction project. It requires the dimensions, where the blocks are to be placed and then calculate the total number of blocks needed for that area. The calculator also helps in estimating mortar. Along with block quantity, it shows you how much cement and sand you may need to hold the blocks together. This is useful for material planning. Anyone can use this calculator easily for their construction project to plan buying the right amount of material or plan their budget. In both cases, the calculator saves time, and aids in better planning of the project’s material and keeps the work tempo smooth.

Working of a Concrete Block Calculator

As highlighted above, it works on the data we input. The result it gives out is based on our inputs. When you are using the block calculator for the wall, you have to enter its dimensions which include:

Wall height
Wall length
Wall thickness
The quantity of Walls

After these, there is another section in which you have to enter the dimension of the Block with mortar size. This is where you have to give the size of the block you need for your project. These dimensions usually are mostly defined in inches. It includes:

Block height
Block length
Block thickness
Block price (this is optional if you need to know the cost too)

After adding this, you have to cut the window section. You have to tell the calculator about the window area in sq ft. Once you have added all these details, calculate, and the result will appear, showing you the number of blocks required for the wall, along with the cost and volume of concrete.

Block Cost Calculator

If you are only looking for a block cost calculator, it works differently. It asks you for the width and height of the block, the block size, and the price per block. Once you enter the calculation, the result is featured on the screen showing the thorough material and cost estimate in the following way:

Number of blocks
Bags of mortar
Quantity of sand
Cost of blocks
Cost of mortar
Cost of sand

Finally, the calculator adds these values and shows the total cost of the project. These are two different examples of concrete block calculators. However, every calculator works in a different way. Some ask for just the dimensions and the block size, some ask for the ratio of concrete and mortar while there are also those that calculate the reinforced material. Now, here we want to clarify that every concrete black calculator works differently and also calculate the result differently. Each calculator has its own built-in formula through which it drafts the result for you.

Formula Used in Block Calculator

There is one simple formula which is used in most of the concrete block calculators. The formula is: Number of Blocks = Block Volume / Wall Volume

How the Calculator Use this Formula to Give the Result

As highlighted above, the working of a concrete block calculator is based on this formula: Number of Blocks = Wall Volume / Block Volume What is block volume and wall’s volume? Here is the explanation: Wall Volume = Length × Height × Thickness of the wall Block Volume = Length × Height × Thickness of a single block This is why most of the calculators demand the dimensions of the wall and block to provide the estimated result. Once you provide these inputs, the calculator divides the total wall volume by the size of one block. The result is the total number of blocks you need. You just provide the dimensions, the rest work is done by the calculator itself. It finds out the wall’s volume first and then the block volume. It then finds out the total number of blocks needed. The calculator gives you the result including the mortar gap. Let’s tell you in detail what does this actually mean, but before that check out this easy example: Assume you are building a wall with the following dimensions:

Wall length = 10.5 ft
Wall height = 10.5 ft
Wall thickness = 9 inches which is 0.75 ft
Block length = 9 inches and 0.75 in feet
Block height = 3 inch = 0.25 ft
Block thickness = 4 inches = 0.33 ft

Now here, all the values have one same unit, which is feet. Now, here, if we go with step by step calculation, the first step includes finding the wall’s volume. So let’s explain you with steps:

Step 1 – Find the Wall Volume

Wall Volume= Length × Height × Thickness Wall Volume = 10.5 × 10.5 x 0.75 = 82.68 ft

Step 2 – Find the Block Volume

Block Volume = Block length x Block height x block thickness Block Volume = 0.75 × 0.25 × 0.33 Block volume = 0.0618 ft

Step 3 – Finding out the Number of Blocks

Number of Blocks = Wall Volume / Block Volume Number of Blocks = 82.68 / 0.0618 = 1338 Now here comes the main concern. When we apply the formula, the answer we get is 1338 which we think is the number of blocks that we need to build the wall. However, this is actually the number of blocks which we need to build the wall but in construction it is adjusted with mortar gaps. So, look at our next step:

Step 4 – Adjust with Mortar Gap

Mortar application is necessary while plantar fills some space between blocks. This reduces the number of blocks required. After adjustment, the number decreased to 909 blocks for this wall. The mortar gap is either calculated manually or through the calculator.

What is the Mortar Gap?

When you build a wall with concrete blocks, the blocks are not placed directly on top of each other. A small gap is always left between them and filled with mortar. Mortar is a mixture of sand and cement that fix them together and make the wall stand firm without any support. This space filled with mortar is called the mortar gap or mortar joint. It holds the blocks and increases the strength of the wall and also makes it stable and even. The size of the mortar gap usually ranges between 10 mm to 12 mm which is about 0.4 to 0.5 inch. When we first calculated 1338 blocks, we did it without considering the mortar gap. That means we assumed every inch of wall space is filled with blocks only. But in real construction, that is not the case. Each block is separated by a thin layer of mortar that measures around 10 – 12 mm thick. This is why the effective block size increases. When mortar is added around a block, it makes the block take up more space in the wall. Just imagine a block is of: 9 in × 4 in × 3 in Now, when mortar is applied around it, this might make it measure about 9.4 in × 4.4 in × 3.4 in What here we see is the block volume increases. The wall’s total volume doesn’t change, but now each block with mortar occupies more space. So, less blocks are required to build the wall because every block with mortar covers more volume. In Our Example: Raw calculation without mortar = 1338 blocks With 12 mm mortar joint included = 909 blocks So the difference is because the calculation is adjusted for the mortar layer, which reduces the total count by about 30%.

Factors That Can Affect the Accuracy of the Calculator Result

A concrete block calculator gives results based on the values you enter but in actual construction, some conditions can slightly change the final requirement. This is why people usually misunderstand the result of the calculator. They assume the calculator provides the final estimate of their construction. However, the calculator just gives an estimate and other factors are yet to be included. These include:

Wall plastering – In this mortar gap is usually not considered because the wall has to be plastered later and may require less mortar application.
Irregular block sizes – The thing that everyone must understand. Not every block is perfectly sized and shaped. So understand that this can affect the block count.
Cutting of blocks – Edges and corners require cutting blocks, and this can increase the block requirement.
Local construction practices – Every area and city has different building methods and this might affect the material estimate.

So, this is all about concrete block calculators. It is a useful tool that is available easily and aids in the construction process. It saves time and effort spent in manual calculation. Moreover, it also reduces the chance of errors and gives accurate results. In the end, we must say that building with concrete blocks is a wise decision because concrete blocks are durable and longlasting. To get help with calculation, a calculator can guide you better. Having a calculator at hand simply makes the planning part easier. So use a concrete block calculator online and save your time and start your project with confidence.

Frequently Asked Questions

Can I calculate the cost of construction with a concrete block calculator?

No, the fact is a concrete block calculator just gives you the estimate of the number of concrete blocks needed for the required construction and the cost associated with it. It does not calculate the whole construction cost for you. Although some calculators include block price, mortar cost, reinforced material cost, etc and give you a full material and cost estimate, it is always better to contact your contractor for better guidance.

Can I use the concrete block calculator for any block size?

Yes, you can use the calculator for any block size. For this you have to enter your block’s right dimension you are using for the construction and based on your project needs.

Does the concrete block calculator cut for windows and doors?

Yes.there are calculators that allow you to enter the size of windows and doors, and they automatically subtract that area from the wall calculation.