Short answer
Where 60 bricks per m2 comes from
A wall is a grid of bricks plus mortar. Each brick takes up its own face plus one mortar joint along the length and one along the height. So the space each brick fills on the wall is:
(brick length + joint) × (brick height + joint)
A standard UK brick is 215 mm long and 65 mm high on the face, and 102.5 mm deep, as builders' merchants Beesley & Fildes and Howarth Timber both state. Howarth gives a typical mortar joint of about 10 mm. Put those into the formula:
- (215 + 10) × (65 + 10) = 225 × 75 mm
- 0.225 m × 0.075 m = 0.016875 m² per brick
- 1 ÷ 0.016875 = 59.3 bricks per m2
Rounded, that is the familiar 60 per m2. Beesley & Fildes gives 60 for a half-brick or single-layer wall and 120 for a one-brick or two-layer wall.
Half-brick versus one-brick walls
The difference is wall thickness, not face size.
- Half-brick wall: one layer of bricks laid lengthways. The wall is one brick's depth thick, about 102.5 mm. About 60 per m2.
- One-brick wall: two layers side by side, so the wall is about one brick's length thick. About 120 per m2.
- Cavity wall: two separate leaves with a gap between them. Count each leaf on its own. If both are brick, double the half-brick figure. If the inner leaf is block, count bricks and blocks separately.
Works out material quantities and measurements for building jobs, metric first with an imperial mode.
Get it on Google PlayFree with a small banner ad and an occasional full-screen ad after you save. Every calculator is free. A one-time Pro unlock removes the ads, allows unlimited saved jobs, and lets you send a job's materials list to WhatsApp, SMS or email. There is no subscription.
Construction Calc's Blocks & Bricks estimator works out units for one leaf of wall. Enter the wall width and height, choose a preset (UK brick 215 × 65 mm, UK block 440 × 215 mm, US modular brick or US CMU block) or enter your own length, height and mortar joint, and set a waste percentage. It defaults to 10% waste and rounds up. For a one-brick or two-leaf brick wall, double the result.
Worked example
A garden wall 5 m long and 1.8 m high, built as a half-brick wall in standard UK bricks.
| Step | Working | Result |
|---|---|---|
| Wall area | 5 × 1.8 | 9 m² |
| Bricks, no waste | 9 ÷ 0.016875 | 533.3 |
| With 5% waste | 533.3 × 1.05, rounded up | 560 |
| With 10% waste | 533.3 × 1.10, rounded up | 587 |
Using the rounded rule of 60 per m2 instead gives 540 before waste, slightly more than the exact 533. Both are close enough to order from, as long as you add waste.
If the wall has openings, such as a gate or window, work out their area and take it off before you multiply. A 1 m × 1.8 m gap in the example wall removes 1.8 m², or about 107 bricks before waste.
How much waste to add
Howarth suggests adding around 5 to 10% extra bricks for breakage, cutting and wastage. Beesley & Fildes also advises buying more than you need, because waste is inevitable. As a guide:
- Plain straight wall with few cuts: the lower end, around 5%.
- Corners, piers, openings and lots of cut bricks: the higher end, around 10%.
- Reclaimed bricks: sort them before you count, because damaged ones will not all be usable.
Other brick sizes
The 60 figure only applies to the standard UK size. Other countries use different bricks, so the count changes.
Littlehampton Bricks, an Australian manufacturer, gives the standard Australian brick as 230 mm long and 76 mm high, with a mortar joint close to 10 mm. That works out to about 48.5 bricks per m2, and it says most professionals calculate at 50 per m2 to allow for breakages and cuts.
For any brick, the method is the same: add the joint to each face dimension, multiply, and divide 1 m² by the result. This matters for imported bricks, reclaimed bricks of unusual sizes, and anything sold as a special shape.
How the mortar joint changes the count
The joint is part of the formula, so a thicker or thinner joint changes how many bricks fit in a square metre. With a standard 215 × 65 mm brick:
| Joint | Space per brick | Bricks per m2 |
|---|---|---|
| 8 mm | 223 × 73 mm | 61.4 |
| 10 mm | 225 × 75 mm | 59.3 |
| 12 mm | 227 × 77 mm | 57.2 |
For the 9 m² garden wall above, a 12 mm joint needs about 515 bricks before waste instead of 533. The difference is small per square metre but adds up on a large wall. If your bricklayer works to a joint other than 10 mm, use their figure. In Construction Calc, choose the Custom option in Blocks & Bricks and enter the brick size and your joint. The UK presets use a 10 mm joint.
What about blocks
The same formula works for concrete blocks. A UK block with a 440 × 215 mm face and a 10 mm joint fills 0.45 × 0.225 m, which is 0.10125 m² per block. That gives 9.88 blocks per m2, close to 10. Because blocks are larger, each cut or broken block is a bigger share of the wall, so do not skip the waste allowance.
What this does not cover
- Mortar. You also need to work out sand and cement for the joints. That depends on joint thickness, the mix and the bond, and is not part of the brick count.
- Bond patterns. Decorative bonds that use headers on the face change the count. Work from the bond you are actually building.
- Foundations. A wall needs a footing. If you are pouring a strip or pad, the concrete slab calculator will give you volume and bag count for a rectangle, and for post holes see how much concrete for a fence post.
