Brick calculator — how many bricks do you need for a wall?

About 50 bricks per m² for a solid brick (250×120×65 mm) with 10–12 mm joints. The exact number depends on joint thickness and brick format. Always order 10% extra for waste and breakage.

The standard NF brick is 250×120×65 mm. Other common formats: Danish (DF) 240×115×52 mm, double-module (2NF) 250×120×140 mm, clinker brick 240×115×52 mm. This calculator uses NF dimensions.

A 10–15% allowance covers transport and unloading losses (2–3%), cracking during laying (3–5%), cutting at corners and openings (3–5%) and batch-size variations. For small walls under 10 m² use 15%; for larger areas 10% is sufficient.

Solid brick has higher compressive strength (class 15–35), better acoustic insulation and is used for load-bearing walls and foundations. Perforated brick (Max) has holes that reduce weight and improve thermal insulation; it is cheaper but less strong. Both types use the same brick count formula.

Add up all wall areas (external and internal) to be brick-built. Subtract window area (about 1.5 m² each) and door area (about 2 m² for entrance, 1.8 m² for interior doors). Then use the calculator for the total area and add 10–15% waste.

Solid ceramic brick: 1.50–3.00 PLN each; perforated brick: 1.00–2.00 PLN; clinker brick: 3.00–8.00 PLN; silicate brick: 1.20–2.50 PLN. Also budget for mortar (25–40 PLN per 25 kg bag, usage ~15 kg/m²) and masonry labour (60–120 PLN/m²).

Thick joints (10–15 mm) use traditional cement-lime or cement mortar. Thin joints (1–3 mm) are used with precision elements such as hollow clay blocks or AAC blocks. This calculator uses standard 10–12 mm joints. With thin joints the brick count per m² is slightly higher (about 51–52).

Cement-lime mortar (1:1:6 ratio — cement:lime:sand): about 255 kg cement, 130 kg lime and 1130 kg sand per m³. Usage: approximately 15–20 kg per m² of wall at 10 mm joint. Ready-mix bags (25 kg) yield about 12–15 litres of mortar each.

Brick bonding is the arrangement of bricks so that vertical joints in adjacent courses are offset by at least 1/4 of a brick length (about 6 cm). This distributes loads across the whole wall, prevents cracking along joints and ties corners and wall junctions. Common bonds: stretcher, English, Flemish, and Polish (Wendish).

An experienced bricklayer can lay about 200–400 bricks per day on a standard load-bearing wall. A 12 m² wall with about 600 bricks takes roughly 2–3 working days. Mortar reaches 70% strength after 7 days and full strength after 28 days — do not load the fresh wall for at least 3–5 days.