Builder AI Tools › Materials calculators
Brick and block calculator
Enter the wall size and type. You get the number of bricks or blocks, wall ties for cavity walls, and the cement and building sand for the mortar.
- Wall area
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- Bricks
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- Blocks
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- Wall ties
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- 25 kg cement
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- Building sand
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Bricks 215 × 102.5 × 65 mm and blocks 440 × 215 mm, with 10 mm joints. Mortar includes 10% waste.
How many bricks per m²?
A standard UK brick is 215 × 102.5 × 65 mm. With a 10 mm mortar joint each brick takes up 225 × 75 mm of wall face, so one square metre holds 1 ÷ (0.225 × 0.075) = 59.3 bricks. Most people round this to 60 per m² for a half-brick (single skin) wall, and 120 per m² for a solid one-brick wall.
Standard 440 × 215 mm concrete blocks work the same way: 1 ÷ (0.45 × 0.225) = 9.9 blocks per m², usually rounded to 10.
| Wall | Per m² | Mortar per m² |
|---|---|---|
| Half-brick (102.5 mm) | 60 bricks | about 0.022 m³ |
| One-brick (215 mm) | 119 bricks | about 0.05 m³ |
| 100 mm blockwork | 10 blocks | about 0.008 m³ |
| Cavity wall (brick + block) | 60 bricks + 10 blocks + 2.5 ties | about 0.03 m³ |
Worked example: a 6 m garden wall, 1.8 m high
- Area: 6 × 1.8 = 10.8 m².
- Bricks: 10.8 × 59.3 = 640, plus 5% waste = 672 bricks. Buy in packs, and keep a few back for repairs.
- Mortar at 1:4: about 4 bags of cement and 0.43 tonnes of building sand.
A rule of thumb that matches the calculator: every 1,000 bricks in a half-brick wall need about 6 bags of cement and just over half a tonne of sand at 1:4.
Choosing a mortar mix
- 1:4 (cement : soft building sand) is the everyday mix for walls above damp-proof course level.
- 1:3 is stronger, used below DPC, for copings and in very exposed spots.
- 1:5 or 1:6 with plasticiser or lime suits sheltered walls and softer bricks, which need a mortar weaker than the brick so cracks follow the joints.
Always check what the brick manufacturer recommends, and match existing mortar when extending or repairing.
Cavity walls and wall ties
A cavity wall has an outer leaf of brick and an inner leaf of block, tied together with stainless steel wall ties. The standard spacing is 900 mm horizontally and 450 mm vertically, which is about 2.5 ties per m², with extra ties around openings (at 300 mm centres up each side). The calculator counts the general ties; add a few for each window and door.
Tips
- Deduct doors and windows, but do not deduct small openings like air bricks.
- Waste is higher with cut-heavy work such as piers, curves and decorative bonds: use 10% there.
- Order all facing bricks from one batch, or mix packs as you go, to avoid visible colour bands.
Questions
How many bricks are in a pack?
It depends on the brick and supplier, often around 400 to 500. Check the merchant's listing and divide your total by the pack size.
How many bricks can a bricklayer lay in a day?
Commonly 300 to 500 on straightforward walling, fewer on detailed work. Use the labour calculator to turn that into days and cost.
How much sand and cement do I need for 1,000 bricks?
For a half-brick wall at 1:4, about 6 to 7 bags (25 kg) of cement and 0.6 to 0.7 tonnes of building sand, including a little waste.
Does the calculator include the foundation?
No. Use the concrete calculator for strip footings, and the excavation calculator for the trench.
Results are estimates for planning and ordering. Check quantities with your supplier and product data sheets, and anything structural or regulated with a qualified professional. See our terms.