How it is calculated
The calculator takes the wall area minus doors and windows and finds how many units fit in one square metre including the joint. A reserve covers broken and cut units. The mortar volume is the wall volume minus the volume of the units themselves.
Formula
Units per m² = 1 ÷ ((length + joint) × (height + joint))Units = net area × units per m² × (1 + reserve)Mortar = wall volume − units × unit volumeExample
A wall 6 m long and 2.7 m high with 2 m² of openings, built from 250 × 65 mm bricks with 10 mm joints, needs 765 bricks with a 5 % reserve and about 0.28 m³ of mortar for a 120 mm wall.
Tips from practice
- Aerated blocks are laid on thin-bed adhesive with 2–3 mm joints: enter 3 mm.
- Buy all face bricks from one batch: the colour varies between batches.
- Keep the wall thickness equal to the brick or block width you build with.
Questions and answers
How many bricks are in one square metre?
About 51 bricks of 250 × 65 mm with 10 mm joints in a single-brick-wide (120 mm) wall.
How many aerated blocks per m²?
With 600 × 200 mm blocks and 3 mm joints, about 8.2 blocks per square metre.
How much mortar per m² of brick wall?
For a 120 mm wall, about 0.02 m³ (20 litres) per square metre.
Found a mistake in a formula? Write to contact@planicalc.com