Work out bricks and mortar
Standard UK brick 215 × 102.5 × 65 mm with 10 mm joints: 60 bricks per m² for a half-brick wall, 120 for a one-brick (215 mm) wall.
Openings to take off
Mortar = joint volume from the brick size + the extra % (filled frogs, droppings, thicker beds). Building sand ≈ 1.6 t per m³ of mortar; cement at 1.4 t/m³ loose.
Quantities are estimates for ordering. Check the specification, the brick manufacturer's data and the mortar designation required.
Bricks per m² and mortar quantities
The figures the calculator uses, so you can check them or price from them.
| Wall | Bricks / m² | Joints m³/m² | +60% m³/m² | m³ / 1,000 |
|---|---|---|---|---|
| Half-brick (102.5 mm) | 60 | 0.0176 | 0.0282 | 0.48 |
| One-brick (215 mm) | 120 | 0.0452 | 0.0724 | 0.61 |
“Joints” is the volume of the 10 mm beds and perpends worked out from the brick size. The next columns add the 60% site allowance used by the calculator for filled frogs, droppings and slightly thicker beds.
| Mix | Mortar m³ | Building sand | Cement (25 kg) |
|---|---|---|---|
| 1:3 | 0.48 | 0.76 t (31 bags) | 9 bags (222 kg) |
| 1:4 | 0.48 | 0.76 t (31 bags) | 7 bags (166 kg) |
| 1:5 | 0.48 | 0.76 t (31 bags) | 6 bags (133 kg) |
| 1:6 | 0.48 | 0.76 t (31 bags) | 5 bags (111 kg) |
Mix is cement : building sand by volume, with plasticiser for 1:5 and 1:6. Sand at about 1.6 t per m³ of mortar, cement at 1.4 t/m³ loose.
How many bricks in a square metre?
A UK metric brick is 215 × 102.5 × 65 mm. With a 10 mm joint each brick takes up 225 × 75 mm of wall face, so one square metre holds 1 ÷ (0.225 × 0.075) = 59.3 bricks. Bricklayers round that to 60 per m² for a half-brick (single skin) wall in stretcher bond, and 120 per m² for a one-brick wall such as English or Flemish bond, which is two skins thick.
Working it out
- Wall area = length × height. Take off the windows and doors.
- Bricks = net area × 60 (half-brick) or × 120 (one-brick).
- Add waste for cuts and breakages — 5% is usual for plain walls, more for lots of cutting, piers or a fussy facing brick.
Example: a wall 5 m long and 2.4 m high with one 1.2 × 1.2 m window is 12 − 1.44 = 10.56 m². Half-brick: 10.56 × 60 = 634 bricks, plus 5% = 666.
Mortar, sand and cement
The joints of 1,000 bricks in a half-brick wall hold about 0.30 m³ of mortar. On site you use more — frogs laid uppermost and filled, mortar dropped, beds a little thicker — so the calculator adds 60% by default, giving about 0.48 m³ per 1,000. That sits between the common rules of thumb of roughly half a tonne to a tonne of building sand per 1,000 bricks. Change the extra % to match how your gang works.
A cubic metre of mortar needs roughly a cubic metre (about 1.6 tonnes) of building sand, because the cement and water fill the gaps between the grains. Cement is the sand volume divided by the mix number.
Which mix?
Follow the specification. As a guide, stronger mixes such as 1:3 or 1:4 are used below DPC, for copings and in exposed work, while 1:5 or 1:6 with plasticiser is common for general walling above ground. Don't use a mortar much stronger than the brick.
Questions bricklayers ask
How many bricks are in a square metre?
About 60 for a half-brick wall using standard 215 × 102.5 × 65 mm bricks with 10 mm joints (59.3 exactly), and about 120 for a one-brick (215 mm thick) wall. Add around 5% for waste.
How much sand and cement do I need for 1,000 bricks?
The joints alone take about 0.30 m³ of mortar per 1,000 bricks in a half-brick wall; allowing for frogs and waste brings it to about 0.48 m³. At 1:4 that is about 0.77 t of building sand (31 × 25 kg bags) and 7 bags of cement; at 1:6 about 5 bags of cement.
How do I calculate bricks for a wall with a window?
Multiply length by height for the wall area, subtract each window and door (width × height), then multiply the net area by 60 for a half-brick wall or 120 for a one-brick wall and add 5% for waste.
Should frogged bricks be laid frog up?
Yes. Single-frogged bricks are normally laid frog up with the frog filled with mortar, which gives a stronger wall but uses more mortar than laying them frog down. Allow for it in your mortar quantity.
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See Graftum estimatingQuantities are estimates for ordering. Check the specification, the brick manufacturer's data and the mortar designation required.