By volume, one 600 × 200 × 100 mm AAC block equals 6.8 standard 9″ × 4″ × 3″ bricks (6.1 once the mortar joints are counted), a 600 × 200 × 200 mm block equals 13.6 bricks (11.7 laid), and a 9-inch 600 × 200 × 225 mm block about 15.3 (13.1 laid). A cubic metre of wall takes about 436 bricks or 71 four-inch blocks. The brick calculator below switches between the two.
The volume arithmetic
A standard Indian brick is 9″ × 4″ × 3″ = 228.6 × 101.6 × 76.2 mm, or 0.00177 m³ of solid clay. With a 10 mm mortar joint added to each dimension it occupies 0.0023 m³ of wall, so a cubic metre of wall holds about 436 bricks. An AAC block is treated the same way: solid volume, then volume with joints. Dividing one by the other gives how many bricks the block replaces.
bricks per block = (block l × h × w) ÷ (0.2286 × 0.1016 × 0.0762)
One AAC block in bricks, by common Indian block sizes| AAC block | Solid volume | Bricks (solid) | Bricks (laid, 10 mm joints) | Blocks per m³ |
|---|
| 600 × 200 × 100 mm (4-inch) | 0.012 m³ | 6.8 | 6.1 | 71 |
|---|
| 600 × 200 × 150 mm (6-inch) | 0.018 m³ | 10.2 | 8.9 | 48.8 |
|---|
| 600 × 200 × 200 mm (8-inch) | 0.024 m³ | 13.6 | 11.7 | 37.2 |
|---|
| 600 × 200 × 225 mm (9-inch) | 0.027 m³ | 15.3 | 13.1 | 33.2 |
|---|
Worked example, 600 × 200 × 100 mm. Solid volume = 0.6 × 0.2 × 0.1 = 0.012 m³. Divided by 0.00177 m³ per brick = 6.8 bricks. With joints: 0.61 × 0.21 × 0.11 = 0.01409 m³ ÷ 0.0023 m³ = 6.1laid bricks. The "laid" figure is the one to use when converting an existing brick count into blocks, because it includes the mortar both units would carry.
Worked wall: 10 ft × 10 ft, 9-inch thick
The wall is 2.124 m³. In brick it takes 972 bricks (5% wastage included), 2.7 bags of cement and 19.6 cft of sand for 1:6 mortar. The same volume in 100 mm AAC units is 159 blocks with 1.7 bags and 12.7 cft — and in 200 mm blocks about 83 blocks. In practice a 9-inch AAC wall is built from a single 225 or 230 mm block, so count by face area: 100 sq ft × 0.73 ≈ 77 blocks with wastage.
Mortar versus adhesive
Bricks are laid in 10–12 mm cement-sand mortar, and the joints are a fifth of the wall volume. AAC blocks are dimensionally accurate, so they are laid in a 2–3 mm polymer-modified thin-bed adhesive — far less material, no curing water, and a flatter wall that takes 6–8 mm plaster or gypsum instead of 12–15 mm. If a site lays AAC in conventional mortar (common in smaller towns), the calculator's 10 mm-joint figures apply. Either way, use the block maker's recommended adhesive and a lintel band over openings as your engineer details.
Assumptions
- Brick 9″ × 4″ × 3″ nominal; fly-ash bricks share this size, so the same conversions apply.
- AAC blocks at the common Indian 600 × 200 mm face; some makers supply 625 × 240 mm — recompute with their size.
- 10 mm joint for the "laid" column and the calculator; thin-bed adhesive reduces the joint to 2–3 mm and raises blocks per m³ by roughly 10%.
- Counts are planning quantities. Strength grade, wall thickness and reinforcement are structural decisions for a qualified engineer.
Frequently asked questions
9 inch AAC block equals how many bricks?
A 600 × 200 × 225 mm block is 0.027 m³ of solid material, which is 15.3 times the 0.00177 m³ of a 9″ × 4″ × 3″ brick. Counting a 10 mm mortar joint on each unit, one laid 9-inch block occupies the wall space of about 13.1 laid bricks. Some makers sell 230 mm or 250 mm blocks; scale the figure by the thickness.
How many AAC blocks replace 1,000 bricks?
Divide by the bricks-per-block figure: 1,000 ÷ 6.1 ≈ 164 four-inch (100 mm) blocks, or 1,000 ÷ 11.7 ≈ 85 eight-inch (200 mm) blocks, for the same volume of wall including joints. Add 3–5% for cutting at corners and openings.
How many AAC blocks are there in 1 m³ and per square foot of wall?
71 blocks of 600 × 200 × 100 mm per m³ laid with 10 mm joints (about 83 per m³ with thin 3 mm adhesive joints), versus about 436 bricks per m³. On the wall face, a 600 × 200 mm block covers 0.126 m² including joints — 0.73 blocks per sq ft of wall, whatever the thickness — against roughly 9–10 bricks per sq ft of 9-inch wall.
Do AAC blocks use less mortar than bricks?
Much less. In the calculator, a 10 × 10 ft 9-inch wall needs 19.6 cft of sand and 2.7 bags of cement as 1:6 mortar with bricks, but 12.7 cft and 1.7 bags with 10 mm-jointed AAC, because far fewer joints exist. Laid properly with a 2–3 mm thin-bed block adhesive the cement-sand mortar disappears entirely: one 40 kg bag of adhesive typically covers about 90–110 sq ft of 100 mm wall — confirm with the adhesive maker's data sheet.
Is an AAC block wall cheaper than a brick wall?
Per cubic metre the blocks usually cost more than bricks, but you buy far fewer units, use a fraction of the mortar, lay the wall two to three times faster, and the lighter wall (about a third of the weight of brick) can let the engineer trim the frame. Plaster is thinner too. Whether it nets out cheaper depends on local brick and block prices, so price both from the calculator's quantities. The structural decision — block strength grade, lintels, frame sizes — stays with your engineer.
Reviewed on 6 October 2026. These are preliminary planning quantities from standard methods — actual consumption varies with workmanship, wastage and site conditions. VastuCalc does not provide structural design; sizes, grades and reinforcement must come from a qualified engineer.