How many breeze blocks per m2?

9.88, the same as any 440 x 215 mm block: breeze block is the everyday name for concrete blocks, and 440 x 215 mm is the standard UK block face. A block with a different face size follows the formula further down.

How many concrete blocks per m2?

9.88 for the standard 440 x 215 mm block with a 10 mm joint, whether it is 100, 140 or 215 mm thick. The US 8 x 8 x 16 in block (actual 15 5/8 x 7 5/8 in, 3/8 in joint) is 12.11 per m², or 1.125 per square foot.

How many blocks per m2 laid flat?

20.2 for a 100 mm block laid flat, because the face is then 450 x 110 mm with the joints, and the wall is 215 mm thick. A 140 mm block laid flat is 14.8 per m². Laid flat a wall takes about twice the blocks, so it is used for thicker or stronger walls, not to save blocks.

How many blocks in a square metre with waste?

10.4 with the usual 5% for cuts and breakages, and more on a wall with many openings and corners. Round up the total for the wall, not each square metre.

How much mortar per m2 of blockwork?

About 0.9 bags of 25 kg ready-mixed mortar per m² of 100 mm block: 12 blocks a bag plus 10% for what stays on the board. Mixing your own, Tarmac (2026) puts one tonne of lime:sand mortar, gauged with cement on site, at about 600 blocks, so 16.5 kg of lime:sand per m².

How many 140 mm or 215 mm blocks per m2?

9.88 and 9.88: the same face, so the same count as a 100 mm block. The solid 140 mm block takes a wider bed: a 25 kg bag lays about 9 of them against 12 of 100 mm, while the 215 mm hollow block is bedded on its face shells, 12 a bag.

How many 8x8x16 blocks per square foot?

1.125: each block and its joint cover 16 x 8 in, which is 0.889 sq ft. A 100 sq ft wall is 113 blocks before waste; the concrete blocks for a wall guide has the US wall sizes.

How many blocks per m2? 440 x 215 concrete and breeze blocks, mortar and waste

There are 9.88 blocks per m² of wall for a standard 440 x 215 mm concrete or breeze block laid with a 10 mm joint, because each block and its joint cover 450 x 225 mm. Order 10.4 per m² with 5% for cuts, and 19.8 for two leaves. The thickness does not change the count: 100, 140 and 215 mm blocks share the face. Mortar is about 0.9 bags of 25 kg per m², and laid flat a 100 mm block is 20.2 per m². In US units an 8 x 8 x 16 in block is 1.125 per square foot.

Open the brick and block calculator

Blocks per square metre by block

Standard UK blocks are 440 x 215 mm on the face and come in several thicknesses. The thickness changes the weight, the mortar bed and the wall, not the number per square metre. Laid flat, the thickness becomes the face height and the count changes.

440 x 215 mm blocks, 10 mm joint, single leaf
Block	Per m²	With 5%	Laid flat, per m²	Blocks per 25 kg bag
Solid block, 100 mm	9.88	10.4	20.2	12
Solid block, 140 mm	9.88	10.4	14.8	9
Hollow block, 215 mm	9.88	10.4	9.9	12

Blocks and mortar for 1 to 50 m²

100 mm blocks, single leaf, counted by area: blocks before waste, to order with 5%, 25 kg bags of ready-mixed mortar with 10% extra, or tonnes of lime:sand to gauge with cement on site. For two leaves, double every column.

100 mm block, 10 mm joint, 5% waste on blocks, 10% on mortar
Wall area	Blocks	To order (+5%)	25 kg mortar bags	Lime:sand (t)
1 m²	10	11	1	0.02
2 m²	20	21	2	0.03
5 m²	50	52	5	0.08
10 m²	99	104	10	0.16
15 m²	149	156	14	0.25
20 m²	198	208	19	0.33
25 m²	247	260	23	0.41
50 m²	494	519	46	0.82

How the 9.88 is worked out

A block covers its own face plus one joint along the top and one along the end: 440 + 10 = 450 mm long and 215 + 10 = 225 mm high, so 0.10125 m². One square metre divided by that is 9.877 blocks. The same sum works for any block: 1 / ((length + joint) x (height + joint)), in metres. The brick and block calculator does it for a wall with openings, and the concrete block calculator counts whole courses, mortar bags and the grout for reinforced cells.

Two leaves, cavity walls and laid flat

Two leaves of block side by side: 19.8 per m², each leaf counted on its own.
Cavity wall of brick outside and block inside: the block leaf is 9.88 per m² and the brick leaf is in the 73mm and UK bricks per m² guide or the bricks per square metre guide.
Laid flat: 20.2 blocks of 100 mm per m², a wall 215 mm thick.

Before you order

Take doors and windows off the area first; the calculator removes them for you. Round up the whole wall, then buy by the pack the yard sells.
A garden or boundary wall is a job with a footing, bars and a bond beam: the building a block wall guide has blocks and mortar for 2 to 10 m walls in order of work.
Blocks are heavy and the thickness sets the weight per pack: check what the delivery can unload where you need it.

Frequently asked questions

How many blocks per m2?: 9.88 blocks of 440 x 215 mm per square metre with a 10 mm joint: 1 m² / (0.45 m x 0.225 m), about 10 per m². With 5% for cuts, order 10.4 per m²; 10 m² is 99 blocks, 104 to order.
How many breeze blocks per m2?: 9.88, the same as any 440 x 215 mm block: breeze block is the everyday name for concrete blocks, and 440 x 215 mm is the standard UK block face. A block with a different face size follows the formula further down.
How many concrete blocks per m2?: 9.88 for the standard 440 x 215 mm block with a 10 mm joint, whether it is 100, 140 or 215 mm thick. The US 8 x 8 x 16 in block (actual 15 5/8 x 7 5/8 in, 3/8 in joint) is 12.11 per m², or 1.125 per square foot.
How many blocks per m2 laid flat?: 20.2 for a 100 mm block laid flat, because the face is then 450 x 110 mm with the joints, and the wall is 215 mm thick. A 140 mm block laid flat is 14.8 per m². Laid flat a wall takes about twice the blocks, so it is used for thicker or stronger walls, not to save blocks.
How many blocks in a square metre with waste?: 10.4 with the usual 5% for cuts and breakages, and more on a wall with many openings and corners. Round up the total for the wall, not each square metre.
How much mortar per m2 of blockwork?: About 0.9 bags of 25 kg ready-mixed mortar per m² of 100 mm block: 12 blocks a bag plus 10% for what stays on the board. Mixing your own, Tarmac (2026) puts one tonne of lime:sand mortar, gauged with cement on site, at about 600 blocks, so 16.5 kg of lime:sand per m².
How many 140 mm or 215 mm blocks per m2?: 9.88 and 9.88: the same face, so the same count as a 100 mm block. The solid 140 mm block takes a wider bed: a 25 kg bag lays about 9 of them against 12 of 100 mm, while the 215 mm hollow block is bedded on its face shells, 12 a bag.
How many 8x8x16 blocks per square foot?: 1.125: each block and its joint cover 16 x 8 in, which is 0.889 sq ft. A 100 sq ft wall is 113 blocks before waste; the concrete blocks for a wall guide has the US wall sizes.

How many bricks per square metre (and per square foot)?
Bricks and blocks per square metre and per square foot for the common formats, how the mortar joint changes the count, and what to order for a 10 m² wall.
How many bricks per square foot? Walls, patios and floors
Modular bricks per square foot of wall (about 7) and laid flat on a patio (4.5 to 5), bricks for 100 to 500 sq ft with 5% waste, mortar, and the UK brick per sq ft.
How many bricks do I need for a fire pit? Fire pit brick calculator for 30 to 48 inch pits
A 36 in round fire pit takes 16 modular bricks a course, 84 for 5 courses with 5% waste, and 14 fire bricks a course to line it. 30 to 48 in, square pits.
How many blocks for a retaining wall? (12x4, 16x6 and 18x8 in)
Retaining wall blocks for 10 to 50 ft walls at 1, 2 and 3 ft high in the three common sizes, plus the gravel base and the drainage stone behind the wall, and metric.

Last updated 2026-10-13. Figures are planning estimates from typical product data: check the yield, size or coverage printed on what you buy and round up.