Brick and Block Quantity Calculator

How many bricks do I need?

The number of bricks in a wall is the wall area divided by the area one brick covers together with its mortar joint. Each brick has a joint around it, so one joint thickness is added to both its length and its height:

units per square metre = 1 / [(length + joint) × (height + joint)]

That figure is multiplied by the net wall area, which is the wall area less door and window openings. A waste allowance for breakage and cutting goes on top.

Example

A wall 5 m long and 2.8 m high with a 2 m² door opening has a net area of 12 m². With 19 × 19 cm bricks and a 1 cm joint the module is 20 × 20 cm, so 25 bricks per square metre. That is 300 net and 315 with 5 percent waste.

Concrete and AAC blocks

The calculation is the same. Only the unit size and the joint change. A 39 × 19 cm concrete block with a 1 cm joint needs 12.5 per square metre. A 60 × 25 cm AAC block with a 3 mm thin joint needs about 6.6 per square metre.

Joint mortar

The calculator also gives the geometric volume of the joints: wall volume less the volume of the units. Real mortar consumption is higher, because mortar enters the holes of perforated bricks and some is lost on site.

Limits

Unit sizes vary by manufacturer. The defaults are common nominal sizes, so enter the size of your own product. Nothing is deducted for corner bonding, lintels or bond beams. Structural capacity and seismic behaviour of the wall are outside this tool.