Brick / Block Calculation - How to calculate the number of bricks / blocks needed?

The easy and on  site calculation is done by dividing the area of the wall, to which you need to calculate by the area of one brick or block that you are going to use.

For the calculation the following hypothesis should consider,

1. Allow a 10mm thickness for grout or mortar  joint
2. Allow 10% of wastage

Sample calculation

Let the area of a brick as l X b and area of the wall as w X h. Add 10mm for each to get an area of (l+10) (b+10). Then divide the wall area wh by (l+10) (b+10) to get the number of needed bricks. Then finally add the calculated wastage amount to it.