AAC Block Calculator: Blocks, Adhesive and Mortar
You need about 8.17 AAC blocks per m² of wall for 600 × 200 mm blocks with 3 mm joints, before wastage. A 10 m² wall needs 86 blocks with 5% wastage, plus 2 bags of 40 kg adhesive at 200 mm thickness. Enter your walls below for blocks, m³ and adhesive or mortar after openings.
Estimate AAC blocks and jointing material
Enter each wall once. Openings are physical deductions in m²; subtract columns, beams and lintels from the masonry dimensions as well.
The manufacturer TDS (April 2016, checked 20 October 2026) covers 600 × 200 mm blocks with 3 mm joints. Confirm current coverage before ordering. Block wastage is applied once; adhesive and mortar have no extra loss allowance. Base levelling mortar is separate.
- Net wall face
- 10 m²
- Net masonry volume (includes joints)
- 2 m³
- Blocks before wastage (equivalent)
- 81.693
- Order blocks (rounded up)
- 86 blocks
- Ordered solid block volume
- 2.064 m³
- Adhesive usage, 40 kg bags
- 1.35–1.54
- Whole adhesive bags to buy
- 2
Same net area as a 230 mm red-brick wall: 987 conventional bricks including 5% wastage; 2.83 cement bags and 0.59 m³ sand at 1:6 with 10 mm joints.
Open the brick calculatorQuantity comparison only. Wall thickness, structural suitability, finishes and cost need separate checks.
Check dated AAC block prices per m³ and per block before entering your local material rate.
For solid or hollow concrete masonry and paving, use the block calculator.
Worked example: 4 m × 3 m wall, 2 m² opening
This wall needs 86 blocks of 600 × 200 × 200 mm (2.064 m³) and 2 bags of adhesive.
- Net face area = 4 × 3 − 2 = 10 m². At 200 mm thickness, masonry volume = 10 × 0.2 = 2 m³, including joints.
- Jointed face module = (0.600 + 0.003) × (0.200 + 0.003) = 0.122409 m². Equivalent count = 10 ÷ 0.122409 ≈ 81.69334.
- Order = ceiling(10 ÷ 0.122409 × 1.05) = 86 blocks. Each solid block = 0.6 × 0.2 × 0.2 = 0.024 m³. Ordered solid volume = 86 × 0.024 = 2.064 m³.
- Wall face = 10 × 10.7639 = 107.639 sq ft. At the stated 70–80 sq ft per 40 kg bag, adhesive = 107.639 ÷ 80 to 107.639 ÷ 70 = 1.35–1.54 bags. Round up: 2 bags.
For 10 mm conventional mortar instead: face module = 0.610 × 0.210 = 0.1281 m². Wet mortar = 2 − (10 ÷ 0.1281 × 0.024) ≈ 0.126 m³. At 1:6, dry mortar = wet × 1.33; cement = dry ÷ 7 × 1,440 ÷ 50 ≈ 0.69 bags; sand = dry × 6 ÷ 7 ≈ 0.144 m³. These exclude the base levelling course and handling loss.
The same 10 m² as a 230 mm red-brick wall is 2.3 m³ of masonry: 987 bricks with 5% wastage, 2.83 cement bags and 0.59 m³ sand. Check other sizes in the brick calculator.
Adhesive coverage and estimating assumptions
One 40 kg bag of block adhesive covers 70–80 sq ft of 200 mm AAC wall, and more for thinner blocks. The table is from the UltraTech FIXOBLOCK data sheet, series FB0007, April 2016, page 2, hosted by a distributor; check the current sheet. Sources checked 20 October 2026.
| Block thickness | Wall face coverage |
|---|---|
| 100 mm | 160–180 sq ft |
| 150 mm | 120–140 sq ft |
| 200 mm | 70–80 sq ft |
| 230 mm | 60–70 sq ft |
| Assumption | Basis and source |
|---|---|
| 600 × 200 mm editable face; 100/150/200/230 mm thickness | Listed geometries in the April 2016 TDS. Check delivered sizes. |
| Adhesive at 2–3 mm | Magicrete product guidance, undated, checked 20 October 2026. Its coverage is not substituted for FIXOBLOCK. |
| 10/12 mm conventional mortar and 5% block wastage | Editable estimating scenarios, not code requirements. Geometry uses filled bed and vertical joints; allow separately for site losses. |
| Mortar dry factor 1.33; cement 1,440 kg/m³; 50 kg bags | Same shared assumptions as our cement calculator; these are estimating conversions, not adhesive yield factors. |
| IS 2185 (Part 3):1984 context | BIS product manual, January 2019: AAC block certification context; confirm grade, density and tested dimensions with your supplier. |
Common mistakes when ordering AAC
Most AAC ordering errors come from using floor area for walls or the wrong adhesive coverage for the block thickness.
- Using floor area as wall area. Measure wall faces and remove openings and RCC intrusions.
- Using 100 mm block adhesive coverage for a 200 mm wall, or confusing 25 kg and 40 kg bags.
- Adding a joint to the wall thickness. Face joints repeat along length and height; thickness is the block’s actual width.
- Rounding each wall before adding wastage. The tool totals equivalent blocks and rounds the order once; pallet quantities need a final supplier check.
- Assuming the computed block volume is billable masonry volume. Ordered solid blocks and installed masonry with joints are different quantities.
- Treating quantity savings as structural approval. The designer decides wall thickness, supports, movement joints and connections.
Next: estimate finishes with the plaster calculator, read the brickwork rate guide, or browse all calculators.
Frequently asked questions
How many AAC blocks do I need per square metre?
About 8.17 blocks per m² for a 600 × 200 mm face with 3 mm joints, before wastage: 1 ÷ (0.603 × 0.203) = 8.1693. Multiply by the net wall area, add wastage, then round up once. Block thickness does not change this count.
How many AAC blocks are in one cubic metre?
For 600 × 200 mm blocks: 83.3 at 100 mm thickness, 55.6 at 150 mm, 41.7 at 200 mm and 36.2 at 230 mm. These are solid-volume figures before joints and wastage; suppliers sell by m³, and a pallet count may differ.
How many adhesive bags are needed?
About 1.35–1.54 bags of 40 kg for 10 m² of 200 mm wall, so buy 2. The UltraTech FIXOBLOCK data sheet (April 2016) lists 70–80 sq ft per 40 kg bag for 600 × 200 × 200 mm blocks at 3 mm joints, and 10 m² is 107.64 sq ft. Thinner blocks cover more wall per bag.
Can I use Magicrete, Siporex or Biltech blocks?
Yes. Enter the delivered block’s actual face size and thickness. The adhesive preset is only for UltraTech FIXOBLOCK with 600 × 200 mm blocks; for any other adhesive, enter its stated coverage per 40 kg bag.
Does a thicker block need more blocks?
No. For the same face size, joints and wall area, the block count stays the same. Block volume and adhesive or mortar go up with thickness, which is why adhesive coverage must match the thickness.
Should I choose adhesive or conventional mortar?
Follow the project specification and the block supplier’s instructions. The tool estimates either 2–3 mm thin-bed adhesive or 10–12 mm cement mortar. The base levelling course needs a separate allowance.
What does IS 2185 Part 3 cover?
IS 2185 (Part 3):1984 is the Indian standard for autoclaved cellular (aerated) concrete blocks. BIS’s January 2019 product manual lists its dimension, density, grade and certification tests. It does not set a project’s wall thickness.
Are openings and wastage included?
Yes. Openings entered for each wall are deducted in full. Block wastage is added once to the total count, then rounded up. Adhesive and mortar get no wastage, and the base mortar course is not included.
Walling a whole building? Get a BOQ from your drawings with blockwork measured wall by wall.