How this calculation works
Treat actual brick length plus a head joint and actual face height plus a bed joint as one repeating face module. Divide net wall-face area by that module and apply the entered allowance before rounding up. This is an area-based estimate rather than a resolved bond layout.
Bricks = ceil[(gross face area − openings)/face module area × (1 + allowance)]A worked example
A 3 m × 2 m wall excluding 1 m² has 5 m² net face. A 230 × 75 mm face with 10 mm joints has module area 0.0204 m². With 5% allowance, round to 258 bricks.
Good to know
A geometric material-planning estimate from the entered measurements. Check actual product dimensions and the project layout. No structural suitability, installation specification, local requirements, labor, tax or pricing is determined. Decimal input lists allow up to 6 places and at most 100 entries/rows, each no greater than 1,000,000. Single-leaf repeating face-area estimate only. Edge joints, bond, corners, returns, lintels, wall thickness, mortar volume and reinforcement are not resolved. Defaults are examples, not a prescribed brick size or allowance.
Reference: Brick Industry Association: technical notes on dimensioning and quantities (opens in a new tab) ↗
A face module combines a brick with its repeating joints
Using actual face dimensions alone would ignore the mortar-joint spaces in the wall. This model adds a head joint to brick length and a bed joint to face height, then multiplies those module dimensions.
For a 230 by 75 mm brick face with 10 mm joints, the repeating module is 240 by 85 mm, or 0.0204 m². A 5 m² net wall face therefore contains about 245.098 theoretical modules before any quantity allowance.
That fractional count is an area model. A real bond, corner and boundary layout determines how many whole and cut units are required. It is not enough to divide area and assume every edge will land on a full module.
Keep face quantity distinct from wall design
The rectangle area relationship checks the gross width-times-height calculation before openings are subtracted. Openings must be measured as areas and cannot exceed that gross face area.
The entered allowance is applied before the final count is rounded upward. It is an assumption about extra quantity, not a recommended waste percentage. Bonding, returns, damaged units and cutting may change the appropriate order.
This single-leaf face estimate does not calculate wall thickness, mortar volume, reinforcement, lintels or structural performance. Actual brick face size must also be distinguished from a nominal modular label that may already include a joint.
A few questions, answered
Should I enter actual or nominal dimensions?
Enter actual brick face length and height, then the joints separately. A nominal module that already includes joints would double count them if used as the brick face.
Does this calculate mortar?
No. A face module supports the brick-count estimate; it does not determine mortar volume or mix.
Can a whole-wall opening return zero bricks?
The area arithmetic permits zero net face area. That result does not establish that such a wall layout is meaningful or buildable.