Brick & block calculator

Work out the face of the wall, multiply by the bricks or blocks a m², and add the wastage.

• Area: length × height, less the openings.
• Bricks: a UK standard brick is 215 × 102.5 × 65 mm. With 10 mm joints it takes up 225 × 75 mm of wall, so 59.3 bricks a m², which the trade rounds to 60 (single skin) or 120 (double skin).
• Blocks: 440 × 215 mm, so 450 × 225 mm with the joints: 9.9 a m², called 10.
• Mortar: about 0.03 m³ a m² of single-skin brickwork (roughly 0.5 m³ per 1,000 bricks, frogs and droppings included), 0.01 m³ a m² of 100 mm blockwork. Dry materials take about a third more room than the mortar they make (× 1.33), split by the mix.

A worked example

A 5 m wall, 2 m high, single skin: 5 × 2 = 10 m², × 60 = 600 bricks, + 5% = 630 bricks.

Mortar: 10 × 0.03 = 0.30 m³. At 1:4, 0.30 × 1.33 = 0.399 m³ of dry materials: one part in 5 is cement, about 115 kg (5 bags of 25 kg), and the rest building sand, about 0.51 t.

The weights assume cement at about 1,440 kg/m³ and building sand at 1,600 kg/m³. These are estimates: for structural walls, follow the drawings.