AAC Block Count Calculator
Calculate the number of autoclaved aerated concrete blocks needed for a wall using actual block dimensions, mortar or adhesive joint assumptions, rectangular openings and a separate cutting allowance.
Enter AAC wall dimensions
AAC block quantity
How AAC block quantity is calculated
The calculation uses the net wall area after openings and divides it by the block's repeating face module.
Block module = (block length + joint) × (block height + joint)
Net blocks = net wall area ÷ block module area
Worked example
A 12 m × 3 m wall has 36 m² gross area. After 12 m² of openings, 24 m² remains. A 600 × 200 mm block with a 3 mm joint gives a repeating face module of about 0.121206 m².
A 5% cutting allowance would bring the planning quantity to roughly 208 blocks.
Why actual block counts need a layout check
AAC blocks are often cut around corners, openings and top courses. The geometric count does not know whether a cut piece can be reused elsewhere in the wall.
For a detailed procurement quantity, use the actual wall-by-wall layout and then apply a project-specific cutting allowance.
Joint thickness matters
Thin-joint masonry can use a very different joint dimension from conventional mortar. The joint value therefore should come from the actual approved installation system.
Limitations
This calculator estimates wall-unit quantities. It does not calculate structural capacity, adhesive quantity, reinforcement, lintels, thermal performance or fire performance.
Frequently Asked Questions
How many AAC blocks fit in one square metre?
It depends on block face size and joint. A 600 × 200 mm block is about 8.33 per m² before joints.
Should openings be deducted?
Yes.
Does the joint change block count?
Yes.
Should cutting waste be separate?
Yes, because the allowance is a planning assumption.
Does this calculate block strength?
No.