Walls
Net area = 12.00 m² − 3.33 m² = 8.67 m²
n = 1 / ((0.215 + 0.01) × (0.065 + 0.01)) = 59.26 per m² (sizes in m)
8.67 × 59.26 = 513.8 → +5% = 540 bricks
Waste, mortar & cost
How it's calculated
A = Σ(L × H × qty) − Σ(w × h × qty)n = 1 / ((l + j) × (h + j))⌈ A × n × leaves × (1 + waste %) ⌉m = t × [1 − l × h / ((l + j) × (h + j))]V = A × (2 m + j), j = collar jointV_wet = V × (1 + waste %)V_dry = V_wet × 1.33cement = V_dry × c / (c + s), sand = V_dry × s / (c + s)kg = cement volume × 1440 kg/m³l and h are the length and height of one unit as it shows in the wall face, t is its thickness (the thickness of one leaf) and j is the mortar joint. One unit plus its share of the joints covers (l + j) × (h + j) of wall, so a square metre needs the reciprocal of that. The mortar in a leaf is the part of its volume that is not unit. A wall of two leaves, such as a one-brick wall, has the leaves counted twice plus a collar joint of one joint width between them. The dry volume of the mortar materials is 1.33 times the wet volume (some references use 1.27). Cement and sand are the ratio parts divided by the sum of the parts, and cement mass is its volume times 1440 kg/m³. Metric bags are 50 kg; imperial bags are counted as 1 ft³ (94 lb), the same convention as theconcrete calculator.
Worked example: a brick wall with a door and a window
A wall 5.0 m long and 2.4 m high with a door 0.9 × 2.1 m and a window 1.2 × 1.2 m, built in 215 × 102.5 × 65 mm bricks with 10 mm joints, as a single leaf. 5% extra bricks, 25% extra mortar, mortar 1:4.
| Step | Working | Result |
|---|---|---|
| Net area | 5 × 2.4 − 0.9 × 2.1 − 1.2 × 1.2 | 8.67 m² |
| Bricks per m² | 1 / (0.225 × 0.075) | 59.26 |
| Bricks | 8.67 × 59.26 = 513.8 | 513.8 |
| With 5% waste | 513.8 × 1.05 = 539.5 | 540 bricks |
| Mortar per m² | 0.1025 × (1 − 0.215 × 0.065 / 0.016875) | 0.0176 m³ |
| Mortar with 25% waste | 8.67 × 0.017615 × 1.25 | 0.191 m³ |
| Dry materials | 0.191 × 1.33 | 0.254 m³ |
| Cement (1:4) | 0.254 / 5 × 1440 | 73.1 kg ≈ 1.5 bags |
| Sand | 0.254 × 4 / 5 | 0.203 m³ |
For blocks the method is the same: a 440 × 215 × 100 mm block with 10 mm joints gives 1 / (0.450 × 0.225) = 9.88 blocks per m², so 10 m² of wall needs 98.8 blocks, or 104 with 5% waste.
Assumptions
- Stretcher bond and solid units. Other bonds change the count slightly, and a one-brick wall is counted as two leaves plus a collar joint.
- Unit sizes are actual sizes, not nominal sizes, and the mortar joint is added to each. Check the sizes of the units you will buy: they vary by manufacturer and by country.
- Hollow blocks are bedded on their face shells and use less mortar than this estimate, which treats them as solid. Frogged bricks use more. Filled cores and grout are not included.
- Openings are taken out of the area exactly. Cutting and lintels are covered only by the waste percentage.
- Mortar waste defaults to 25%. Published estimating guides allow about that much, and the geometric volume alone is the minimum.
- The 1.33 dry factor, 1440 kg/m³ cement and nominal volume mixes are common rules of thumb. Real mortar is specified under BS EN 998-2 or ASTM C270.
- Metric bricks of 215 × 102.5 × 65 mm are used in the UK and are the size most often given for clay and cement-sand bricks in Malaysia. Local sizes vary (for example 210 × 100 × 65 mm), so use the custom size when yours differs.
- Wall ties, damp-proof courses, insulation, reinforcement and mortar lost in the joints beyond the waste percentage are not included.
Frequently asked questions
How many bricks are in a square metre of wall?
About 59 to 60 for a 215 × 65 mm face with 10 mm joints, in a single-leaf (half-brick) wall. A one-brick wall has two leaves, so it needs about 118.
How many blocks are in a square metre?
About 10 for the common 440 × 215 mm block face with 10 mm joints (9.88 exactly).
How many bricks per square foot?
A modular brick (7⅝ × 2¼ in actual) with a ⅜ in joint comes to 6.86 per ft². The Brick Industry Association quotes 6.75 per ft², which uses the nominal 8 × 2⅔ in coursing. The calculator uses the actual size plus joint, which gives about 1.6% more.
How much mortar for 1000 bricks?
About 0.3 m³ of wet mortar with 215 × 65 mm bricks and 10 mm joints, before waste: 0.0176 m³ per m² divided by 59.3 bricks per m². With the default 25% waste, about 0.37 m³.
Which mortar mix should I use?
1:4 cement to sand is a common general-purpose mix. Stronger mixes such as 1:3 are used for below-ground or heavily loaded work, and leaner mixes such as 1:5 or 1:6 for internal, lightly loaded walls. Specified mortars follow BS EN 998-2 or ASTM C270, so use the mix on the drawings.
How much extra should I order?
5% is typical for bricks and blocks, more for many openings, awkward shapes, or soft or handmade bricks. Mortar is allowed 25% extra by default, because some is dropped, left on the board or over-fills the joints: the geometric amount is the minimum.
Standards and references
- BS EN 771-1 (clay masonry units) and BS EN 771-3 (aggregate concrete masonry units).
- BS EN 998-2: specification for masonry mortar.
- BS EN 1996 (Eurocode 6) and PD 6697: design of masonry structures.
- ASTM C270 (mortar for unit masonry), ASTM C90 (loadbearing concrete masonry units) and ASTM C216 (facing brick).
- Brick Industry Association, Technical Note 10: estimating brick masonry.
This calculator estimates quantities. It does not check wall strength, stability, movement joints or any code requirement. Have the design checked by a qualified engineer.