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Calculate bricks and mortar
Estimates only. Mortar figures assume solid bricks; frogged bricks laid frog-up and perforated bricks take noticeably more. Lime mortars and premixed bags have their own yields, so check the bag or your supplier before ordering. For structural walls, follow your engineer or building regulations.
How the calculation works
Every brick takes up its own face plus one mortar joint on the side and one on top. So the number of bricks in one square metre of a single-leaf wall is:
bricks per m² = 1 ÷ ((brick length + joint) × (brick height + joint)), with sizes in metres.
For a UK brick with a 10 mm joint that is 1 ÷ (0.225 × 0.075) ≈ 59.3, which is why builders quote "about 60 bricks per square metre". A wall one brick thick, or a cavity wall with brick on both sides, uses two leaves, so roughly double. Openings for doors and windows are subtracted before multiplying, and a waste allowance (typically 5% to 10%) covers cuts, breakages and chipped faces.
Mortar is whatever fills the wall that isn't brick: the wall's volume minus the bricks' volume. To turn wet mortar into dry ingredients the calculator uses the common estimating rule that dry materials shrink by about 30% when mixed, a loose bulk density of about 1,440 kg/m³ for cement and 1,600 kg/m³ for damp building sand.
Bricks per square metre by brick standard
Single-leaf (half-brick) wall with a 10 mm (or ⅜ in) joint, no waste:
| Brick standard | Size | Bricks per m² | Bricks per sq ft | One brick thick, per m² |
|---|---|---|---|---|
| UK metric | 215 × 102.5 × 65 mm | 59.3 | 5.5 | 118.5 |
| US modular | 7⅝ × 3⅝ × 2¼ in | 73.8 | 6.9 | 147.6 |
| German NF | 240 × 115 × 71 mm | 49.4 | 4.6 | 98.8 |
| Australian | 230 × 110 × 76 mm | 48.4 | 4.5 | 96.9 |
US tables often say 6.75 modular bricks per square foot because modular coursing assumes three courses rise exactly 8 inches, a slightly thicker bed joint than ⅜ in. German tables quoting 48 NF bricks per m² assume a 12 mm bed joint. Change the joint size in the calculator to match your spec.
Common questions
How many bricks are in a 1 m² wall?
About 60 standard UK bricks for a single-leaf wall, or about 120 for a solid wall one brick thick. Add 5% to 10% for waste.
How many bricks do I need for a garden wall?
Multiply length by height to get the face area, choose "one brick thick" if it is a freestanding 215 mm wall (most garden walls over about 450 mm high are built that way for stability), and add waste. Don't forget the coping or brick-on-edge course on top, which uses extra bricks.
Does the bond pattern change the number of bricks?
Not for the same wall thickness. Stretcher, English and Flemish bonds all fill the same area; they just arrange the headers and stretchers differently. What changes the count is the thickness. See our guide to brick bonds.
How much mortar do I need per 1,000 bricks?
For UK bricks in a single-leaf wall, roughly 0.3 m³ of wet mortar per 1,000 solid bricks before waste, and more for frogged bricks. The calculator works it out from your exact size and joint.
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