For a standard UK brick wall, allow about 60 bricks per square metre for a single-skin (half-brick) wall, or 120 per square metre for a double-skin (one-brick) wall, both with 10 mm mortar joints. Measure your wall, subtract doors and windows, multiply by the per-metre figure, and add 10% for cutting and breakage — that is your order quantity.
The Formula
Every brick takes up its own face area plus one mortar joint on its top and one on its end. So bricks per square metre = 1 ÷ ((brick length + joint) × (brick height + joint)). A UK standard clay brick is 215 × 102.5 × 65 mm; with 10 mm joints its face becomes 225 × 75 mm, or 0.016875 m², giving 1 ÷ 0.016875 ≈ 59.3 bricks per m² — rounded to 60 in the trade. A double skin needs twice as many. Our free Brick Calculator runs this for any brick size, wall size, and bond type, and adds mortar, cement, and sand estimates.
Bricks per Square Metre for Common Bricks
| Brick | Size (L × H) | Joint | Single skin / m² |
|---|---|---|---|
| UK standard clay | 215 × 65 mm | 10 mm | about 59 |
| US modular | 194 × 57 mm | 10 mm | about 73 |
| Indian modular clay | 190 × 90 mm | 10 mm | 50 |
The width (depth) of the brick does not change the count for a single-skin wall — it only affects wall thickness and mortar. Ignoring the joint, by contrast, overestimates the count by roughly 15–20%, because the joints are real area that bricks do not occupy.
A Worked Example
Take a garden wall 10 m long and 3 m high, built in UK standard brick, single skin, with a door and a window totalling 3.3 m² of openings:
- Gross wall area: 10 × 3 = 30 m².
- Net wall area: 30 − 3.3 = 26.7 m².
- Bricks needed: 26.7 × 59.3 ≈ 1,583 bricks.
- Order quantity (+10% waste): 1,583 × 1.10 ≈ 1,742 bricks.
Skipping the openings would have added about 196 bricks you would never lay — and on a house-sized job, that error runs into thousands. Always subtract every door and window first.
Mortar, Cement, and Sand
As a planning estimate, allow roughly 0.3 m³ of wet mortar per 1,000 UK bricks before waste. Dry mortar is about 1.33 times the wet volume (to allow for shrinkage and voids), and a common 1:6 cement-to-sand mix splits that dry volume into one part cement and six parts sand. Cement comes in 50 kg bags, and a cubic metre of cement weighs about 1,440 kg — so for the example wall above (about 1,583 bricks), the mortar is roughly 0.47 m³ wet, needing around 2–3 bags of cement plus sand. These are estimates for ordering, not a substitute for your supplier's figures on a large job.
Bond Patterns: Stretcher, English, and Flemish
The bond is the pattern the bricks are laid in, and it decides the wall's thickness. Stretcher bond lays every brick lengthwise and makes a half-brick (single skin) wall — the usual choice for garden walls and partitions. English bond alternates whole courses of stretchers and headers to make a full one-brick wall, and is the strongest traditional pattern. Flemish bond alternates stretchers and headers within every course, making a one-brick wall with a more decorative face. Both one-brick bonds use roughly double the bricks of a stretcher wall, and both need the same 10% waste allowance — more if the wall has many corners or arches that need cutting.
Clay Brick Sizes Vary by Country
Clay bricks are not one universal size. The UK standard is 215 × 102.5 × 65 mm, the US modular brick is about 194 × 92 × 57 mm, and the Indian modular clay brick is 190 × 90 × 90 mm — while many kilns still make non-standard sizes that vary by a few millimetres. Before ordering, measure ten bricks from your actual delivery, take the average, and run the calculation with those dimensions. A few millimetres per brick, multiplied across thousands of bricks, is the difference between an accurate order and a second delivery.
Ordering Checklist: Before You Call the Supplier
Run through this list before ordering and you will avoid the two classic problems: a second delivery (which costs time and delivery fees) and a pile of leftover bricks (which costs money and garden space). First, measure the wall twice — length, height, and every opening — and write the numbers down. Second, measure ten bricks from the actual batch and average them; kiln sizes vary, and the calculator is only as accurate as the brick size you enter. Third, decide the bond before ordering, because a one-brick wall needs double the bricks of a stretcher wall and you do not want to discover that after delivery.
Fourth, confirm delivery access: a lorry-load of bricks is heavy, and suppliers charge extra if the vehicle cannot reach the site. Fifth, plan storage — bricks should sit on a flat, dry surface, covered, and close to the wall so the bricklayer is not carrying them far. Finally, keep a few spares beyond the waste allowance. A handful of matching bricks, stored dry, is worth its weight years later when a wall needs a small repair and the original batch is no longer made.
Frequently Asked Questions
How many bricks do I need per square metre?
About 60 UK standard bricks per m² for a single-skin wall with 10 mm joints, or 120 for a double skin. Other brick sizes differ: the calculator works it out from the brick dimensions you pick.
How much waste should I add?
10% suits most straight walls; allow 15% for walls with many corners, arches, or openings that need cutting.
What is the difference between English and Flemish bond?
Both are one-brick bonds. English bond alternates entire courses of stretchers and headers, while Flemish bond alternates stretchers and headers within every course, giving a more decorative pattern.
Do I subtract doors and windows?
Yes — enter their total area and the calculator removes it from the wall area first, so you only buy bricks for the solid part of the wall.
Try it yourself: use our free Brick Calculator to get your number in seconds — no sign-up needed.