AAC Block Quantity Calculator
Block count, volume and adhesive from wall size and block format.
Quick answer
With the default inputs: Wall length 10 · Wall height 3 · Openings area 0 m² etc.Total blocks 253 blocks
Edit the inputs below to recalculate.Inputs
Result
Total blocks
253blocks
| Net wall area | 30.00m² |
| Blocks per m² | 8.17blocks/m² |
| Blocks per m³ | 40.8blocks/m³ |
| Wall volume | 6.00m³ |
| Block volume (net) | 5.88m³ |
| Volume per block | 0.0240m³ |
| Joint mortar volume | 0.118m³ |
| Adhesive (1.6 kg/mm·m²) | 148.3kg |
Thin joints need proprietary adhesive, not ordinary cement mortar, which shrinks and cracks. AAC absorbs water quickly so blocks are not wetted before laying, but dust must be brushed off.
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Formula
| Net area | A = length × height − openings |
| Blocks per m² | n = 1 ÷ ((length + joint) × (height + joint)) |
| Total blocks | N = ceil(A × n × (1 + waste)) |
| Mortar | V = wall volume − blocks × block volume |
| Per m³ | n ÷ wall thickness |
A 10 m × 3 m wall, 200 mm thick, 600×200×200 blocks with 3 mm joints and 3% waste: 8.17 blocks per m², 253 blocks in total, 6.00 m³ of wall and about 0.05 m³ of mortar.
AAC block formats and blocks per square metre (3 mm joints)
| Format L×H×T (mm) | Blocks per m² | Blocks per m³ | Weight per block (kg) |
|---|---|---|---|
| 600×200×100 | 8.17 | 81.7 | 7.5 |
| 600×200×150 | 8.17 | 54.5 | 11.3 |
| 600×200×200 | 8.17 | 40.8 | 15.0 |
| 600×200×250 | 8.17 | 32.7 | 18.8 |
| 600×250×200 | 6.52 | 32.6 | 18.8 |
| 600×300×200 | 5.42 | 27.1 | 22.5 |
How to work it out
- Net wall area A = length × height − opening area, measured to the opening size with no deduction for frames.
- Blocks per square metre n = 1 ÷ ((block length + joint) × (block height + joint)). AAC uses thin-bed adhesive with 2-3 mm joints, not 10 mm mortar.
- Total N = ⌈A × n × (1 + waste)⌉. Waste is normally 3-5%, rising to 8% with heavy cutting.
- Adhesive = net area × unit usage, typically 4-6 kg/m² depending on joint thickness.
- Match wall thickness to block thickness (100/120/150/200/250 mm); AAC is not laid two blocks thick.
Where it goes wrong
- Assuming 10 mm joints — AAC uses thin-bed adhesive at 2-3 mm, and 10 mm under-counts by 2-3 blocks per square metre, which is 2,500 blocks on 1,000 m².
- Using ordinary cement mortar — AAC absorbs water heavily and starves ordinary mortar of the water it needs, so bond strength fails; thin-bed or polymer mortar is required.
- Ignoring tie columns, ring beams and lintels — those interrupt the wall, and measuring the full face overstates blocks by 5-8%.
Material and cost
AAC blocks run 280-380 per m³ (about 320 for B06), thin-bed adhesive 600-900 per tonne. A 200 mm wall takes about 0.2 m³ of block and 5 kg of adhesive per square metre — roughly 75 per m² in material and 110-140 per m² including labour.
On site
- Get moisture content below 15% before laying; dampen 1-2 days ahead with no standing water on the surface.
- Keep joints straight and full — both bed and perpend joints need at least 90% fill, or the wall cracks later.
- Fix ties to concrete columns every 500-600 mm and mesh the interface; that is what prevents cracking.
Basis
- GB 50203-2011 Code for acceptance of masonry construction, Chapter 9 (infill walls)
- GB 50574-2010 Unified technical code for wall materials
- JGJ/T 17-2020 Technical specification for application of autoclaved aerated concrete
FAQ
Why not use ordinary cement mortar with AAC?
Ordinary mortar needs 15 mm joints, shrinks more and is stiffer than AAC, so it cracks at the joints; AAC also draws water out fast, leaving the mortar weak. Use thin-bed adhesive at 2-4 mm, fully bedded, and never stronger than the block itself.
Should AAC blocks be wetted before laying?
No — the key difference from fired brick. AAC absorbs slowly, and wetting leaves the surface saturated so the adhesive cannot cure properly, reducing strength; excess water also causes shrinkage cracking. Brush off dust, and in hot dry weather mist lightly but leave no free water.
What waste allowance should I use?
3% for plain walls with a uniform format, 5-8% where there are many openings, corners and irregular areas, and 10% where much cutting is needed. AAC cuts easily but breaks easily, and transit damage counts too — 100 mm boards break far more than thicker ones.
Cite this page
Use this format in reports, method statements or coursework. The link is permanent.
Building Calculator. AAC Block Quantity Calculator. 2026-10-25. https://jianzhujisuan.com/en/aac-block
Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.