Brick Quantity Calculator

Estimating bricks and mortar accurately avoids both shortages that stop work and surplus material that wastes money. This calculator works out how many bricks fit in a wall of a given size and how much cement and sand the mortar needs.

How to use it

1. Enter the wall length, height and thickness, and subtract openings such as doors and windows.
2. Enter the brick size and mortar joint thickness, usually 10 mm.
3. Choose the mortar mix ratio, for example 1:6 for general walls or 1:4 for exposed or load-bearing work.
4. Read the brick count, cement bags and sand volume.

The calculation

A standard modular brick of 190 × 90 × 90 mm becomes 200 × 100 × 100 mm with a 10 mm joint, so one cubic metre of brickwork contains 1 / (0.2 × 0.1 × 0.1) = 500 bricks. Mortar is the wall volume minus the volume of the bricks themselves. Its wet volume is converted to dry volume by multiplying by about 1.27 to 1.33, then split according to the mix ratio. Cement in bags = cement volume / 0.0347 m³ (one 50 kg bag).

Worked example

A wall 5 m long, 3 m high and 0.2 m thick is 3.0 m³, which needs about 1,500 bricks. Brick volume is 1,500 × 0.19 × 0.09 × 0.09 = 2.31 m³, leaving 0.69 m³ of wet mortar, or about 0.92 m³ dry. In a 1:6 mix, cement is 0.92 / 7 = 0.13 m³, about 3.8 bags, and sand is about 0.79 m³.

Practical tips

• Add 5 to 10% wastage for breakage and cutting.
• Check the actual brick size on site; local bricks vary a lot.
• Soak clay bricks before laying so they do not draw water out of the mortar.