How Brickwork & Mortar Quantities are Calculated
Estimating bricks and mortar accurately is critical to prevent material shortages on site or over-purchasing cement and sand.
According to standard Indian Standard (IS) codes and CPWD Specifications, 1 cubic meter of brick masonry using standard modular bricks (190mm × 90mm × 90mm with 10mm mortar joint) contains approximately 500 bricks.
Why We Apply a 1.33 Multiplier for Dry Mortar Volume
When estimating mortar materials (cement and sand):
- The wet volume of mortar is calculated by subtracting the actual volume of bricks from the gross volume of the wall.
- Dry cement and sand shrink when water is added to form mortar paste.
- Mortar is also filled inside brick frogs (indentation on top of bricks) and joint voids.
- Therefore, we multiply the wet mortar volume by a factor of 1.33 (33% extra) to calculate dry material quantities.
Standard Mortar Mix Ratios (CPWD / IS Code)
| Mortar Ratio | Application | Recommended Wall Type |
|---|---|---|
| 1:3 | Rich Mortar | Half Brick (4.5") Outer Partition Walls |
| 1:4 | Medium Rich Mortar | Load Bearing & Foundation Brickwork |
| 1:6 | Standard Mortar | Standard 9" Outer & Inner Brickwork |
Worked Example: A 10 m × 3 m Nine-Inch Wall
A 10 m long, 3 m high wall in 230 mm (9 inch) brickwork with 1:6 mortar, no openings, using standard modular bricks. Gross volume is 10 × 3 × 0.23 = 6.90 m³.
- Bricks: nominal brick volume (190 + 10) × (90 + 10) × (90 + 10) mm = 0.002 m³, so 6.90 ÷ 0.002 = 3,450 bricks. At 5% wastage, order 3,625.
- Wet mortar: actual brick volume is 3,450 × (0.19 × 0.09 × 0.09) = 5.31 m³, leaving 6.90 − 5.31 = 1.59 m³ of wet mortar.
- Dry mortar: 1.59 × 1.33 = 2.115 m³.
- Cement: 1/7 of the dry volume = 0.302 m³ = 435 kg = 8.7 bags, so order 9.
- Sand: 6/7 of the dry volume = 1.813 m³ = 64 cft.
- Labour: at roughly 1.25 mason days and 1.8 beldar days per m³, about 8.6 mason days and 12.4 beldar days.
AAC Blocks vs Red Bricks
The choice changes quantities, dead load and programme, not just unit price. Figures below are typical rather than universal — block sizes and densities vary by manufacturer.
| Factor | Red Brick | AAC Block |
|---|---|---|
| Typical size | 190 × 90 × 90 mm | 600 × 200 × 100–230 mm |
| Units per m³ | ~500 | ~36 to 42 |
| Dry density | 1,800–2,000 kg/m³ | 550–650 kg/m³ |
| Mortar consumption | Higher — many joints | Lower — roughly 60–70% less |
| Dead load on structure | Higher | About one-third |
| Laying speed | Slower | Faster — fewer, larger units |
| Typical use | Load-bearing and general walling | Infill walls in framed structures |
AAC usually wins on programme and on dead load, which can feed back into smaller foundations and less reinforcement on a tall frame. Red brick often wins on unit cost and is still what many CPWD items specify. Price the item you are actually tendering against rather than substituting on assumption — an AAC substitution against a brickwork DSR item is a non-schedule item and needs its own rate analysis.
Frequently asked questions
How many bricks are there in 1 cubic metre of brickwork?
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About 500 standard modular bricks. The calculation uses the nominal brick size — 190 x 90 x 90 mm plus a 10 mm mortar joint on each face, giving 200 x 100 x 100 mm, or 0.002 m³ per brick. One cubic metre divided by 0.002 is 500. Traditional non-modular bricks (230 x 110 x 70 mm) work out closer to 460 to 470 per cubic metre, so confirm the brick size before ordering.
Why is mortar volume multiplied by 1.33?
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For the same reason concrete uses 1.54: dry cement and sand bulk up compared with the wet mortar they produce. Mortar also fills the frog (the indentation on the brick face) and any partly filled joints, which the geometric calculation does not capture. The conventional allowance is 33%, hence the 1.33 factor.
How much cement is needed for 1 cubic metre of 1:6 brickwork?
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Roughly 1.25 bags, or about 63 kg. One cubic metre of brickwork contains around 0.238 m³ of wet mortar; multiplied by 1.33 that is 0.317 m³ dry, of which cement is 1/7 = 0.045 m³, or 65 kg at 1,440 kg/m³. Sand works out to about 9.6 cft. Richer mortars raise this sharply: 1:4 needs closer to 2 bags.
Which mortar ratio should I use — 1:3, 1:4 or 1:6?
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1:6 is the standard for ordinary 9 inch internal and external brickwork. 1:4 is used for load-bearing and foundation masonry. 1:3 is a rich mortar reserved for half-brick (4.5 inch) partition walls, where the thin section needs the extra strength. CPWD specifications state the required ratio item by item, so match the mortar to the DSR item you are pricing rather than choosing by habit.
How do AAC blocks compare with red bricks?
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AAC blocks are far larger (typically 600 x 200 x 100–230 mm), so one block replaces roughly 8 to 12 bricks and mortar consumption drops sharply because there are fewer joints. They are also about a third the density, which reduces dead load on the structure. Red bricks remain cheaper per unit in most markets and are still specified in many government items, so the comparison is item-specific rather than universal.
How many bricks are needed per square metre of a 9 inch wall?
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About 115 bricks per square metre. A 9 inch wall is 230 mm thick, so one square metre of wall face is 0.23 m³ of masonry, which at 500 bricks per cubic metre gives 115. A 4.5 inch (115 mm) wall needs about 57 bricks per square metre.
How much labour does brickwork need?
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As a planning figure, roughly 1.25 mason days and 1.8 beldar (helper) days per cubic metre of masonry. These are indicative rates for straightforward walling — CPWD analysis of rates gives the authoritative figures per item, and they vary with wall thickness, height above ground and the complexity of the work.