# How To Calculate Number Of Blocks For Your Building Project

Hello my good friend!

Do you know the number of blocks needed to complete your building?

This is a very common question asked by prospective homeowners especially after the building design phase.

In fact this will save you much time and money.

However, if you are taking charge of material procurement or just wish to confirm several blocks required for your project, this article will guide you.

A simple one-bedroom apartment is used in this write up for clarity.

Here are the guiding steps to take;

Step 1: Calculate Wall Areas

To calculate wall areas, we will calculate the total length of walls and multiply them by wall height.

Area = Length x Height

To calculate the length, check figure 1 below. Check the length of vertical walls (from left to right), then horizontal walls (from top to bottom)

Wall 1= 8000mm, Wall 2=7755mm, Wall 3 = 3675mm, Wall 4 = 4100mm, Wall 5 = 3900mm, Wall 6=7950mm

Wall 7 = 3525mm, Wall 8 = 5975mm, Wall 9 = 5600mm, Wall 10 = 4425mm, Wall 11= 4200mm

Mathematically, the Sum of all wall lengths is 59,105mm.

Let us assume the height of the wall to be 3000mm.

Rough wall area (Wall area including openings) = 59105mm x 3000mm = 177,315,000mm

Remember we have some wall openings at the entrance, doors and windows. We need to subtract them to get the actual wall area:

In the architectural plan above, we have 6 doors measuring 900mm x 2100mm; 6x900mm x 2100mm= 11,340,000 millimetre square.

We also have 8 windows measuring 1200mm x 1200mm; 8x1200mmx1200mm = 11,520,000 millimetre square.

We have 1 window measuring 600mm x 600mm; 1 x 600mm x 600mm = 360,000-millimetre square.

We have 1 opening measuring 3300mm x 2100mm; 1 x 3300mm x 2100mm = 6,930,000 millimetre square.

Just add up all opening areas:

11,340,000+11,520,000+360,000+6,930,000 = 30,150,000 millimetre square.

Subtract opening area from the rough wall area:

Actual ground floor wall area = 177,315,000 -30,150,000 = 147,165,000 millimetre square.

Area of foundation walls:

Also, please remember we have a foundation. The foundation area depends on the number of courses laid.

For this building, we use four courses of block wall as a foundation (Strip foundation). This is roughly 900mm high.

We simply multiply the perimeter of walls we got in step 1 by the height of the foundation wall. The area is still length x-height. But now the height is 900mm.

Area of foundation wall: 59105mm x 900mm = 53,194,500 millimetre square.

Total wall area = Ground floor wall area + Foundation wall area =147,165,000 + 53,194,500 = 200,359,500 millimetre square.

Step 2: Divide the total wall area by the area of one block.

The area of one block is 225mm x 450mm = 101,250-millimetre square.

Therefore, the total number of blocks for the building project = 200,359,500/101,250= 1978.86 blocks

That is approximately 1,980 blocks. You can decide to add a certain percentage for breakages. If you use good quality vibrated blocks you only need to add a little.