How many bricks per m² of wall?

For a standard brick (190×90×90 mm) with a 10 mm mortar joint in a half-brick (100 mm) wall, you need approximately 50 bricks per square metre of wall face. For a full one-brick (215 mm) wall this doubles to around 100 bricks per m² because the wall is two leaves thick. This calculator handles all combinations automatically.

What is the standard mortar joint thickness?

The standard mortar joint thickness in brickwork is 10 mm (1 cm). This applies to both the bed joints (horizontal) and the perpend joints (vertical). Thinner joints of 6–8 mm are used for face brickwork where a neat finish is required; thicker joints of 12–15 mm are sometimes used with rough or irregular bricks.

How much wastage should I allow for bricks?

A minimum of 10% wastage is recommended for bricks. Bricks can break during delivery, cutting around openings and laying. For complex walls with many openings, curved sections or decorative patterns, allow 15–20%. This calculator defaults to 10% which is the standard for straightforward rectangular walls.

What mortar mix is best for external walls?

A 1:4 or 1:5 cement-to-sand mortar mix is recommended for external brickwork exposed to weather. The 1:3 (rich) mix is stronger but can be too rigid for some brick types, potentially causing cracking. For internal partition walls, a 1:5 or 1:6 lean mix is sufficient. Avoid excessively strong mixes with soft bricks as mortar should ideally be slightly weaker than the brick.

Brick Calculator – Bricks, Mortar & Cement

Wall Dimensions

Wall Length (m)

Wall Height (m)

Wall Thickness

Brick Size

Brick Size Preset

Mortar & Openings

Mortar Joint Thickness (mm)

Mortar Mix

Wastage % (bricks break)

Price per Brick (optional)

Number of Doors

Number of Windows

Each door assumed 2.1 m² · Each window assumed 1.2 m²

Gross Wall Area—

Opening Deductions—

Net Wall Area—

Bricks (without wastage)—

Bricks (with wastage)—

Mortar Volume (dry)—

Cement Bags (50 kg)—

Sand—

— bricks needed

Mortar void volume calculated as (total wall volume − net brick volume) × 1.30 bulking factor. Sand density ≈ 1600 kg/m³. Cement bags at 1:n ratio ≈ 1440/(50×(1+n)) per m³ dry mortar.

Brick Bonding and Wall Thickness

Wall thickness in brickwork is traditionally described in terms of brick lengths. A half-brick wall (100 mm) is one brick wide laid lengthways — used for partition walls and garden walls. A one-brick wall (215 mm) consists of two leaves of bricks tied together — the standard for external load-bearing walls. A one-and-a-half brick wall (325 mm) is used for heavy-duty retaining or boundary walls.

The number of bricks per m² increases proportionally with the number of leaves. Common bonding patterns — stretcher bond, English bond, Flemish bond — affect the appearance and strength of the wall but not the total quantity of bricks significantly for the same thickness.

Stretcher bond: All bricks laid lengthways. Used for cavity walls and half-brick walls.
English bond: Alternating courses of stretchers and headers. Strong and economical.
Flemish bond: Alternating stretchers and headers in each course. Attractive for face brickwork.

What Mortar Mix Should I Use?

The mortar mix (cement:sand by volume) controls the strength and workability of the mortar. The mix should be chosen to suit the brick type, exposure conditions and structural requirements:

1:3 (rich mix): High strength, low permeability. Used in foundations, manholes and below-DPC brickwork in aggressive ground conditions. Avoid with weak or soft bricks.
1:4 (standard external): A good all-round mix for external walls exposed to weather, parapets and chimneys. Provides adequate strength with good workability.
1:5 (standard internal): The most commonly used mix for internal load-bearing and partition walls. Good workability, lower shrinkage risk than richer mixes.
1:6 (lean mix): Low strength, high workability. Suitable for non-load-bearing internal partitions in sheltered locations where structural demands are minimal.

As a general rule, the mortar should be slightly weaker than the brick so that any stress cracking occurs in the mortar joint (which is easy to repoint) rather than through the brick itself.

Frequently Asked Questions

For a standard brick (190×90×90 mm) with a 10 mm mortar joint in a half-brick (100 mm) wall, approximately 50 bricks per m² are needed. For a one-brick (215 mm) thick wall — two leaves — this doubles to roughly 100 bricks per m². For a modular brick (230×110×76 mm) with 10 mm joints, the count is around 45 bricks per m² per leaf.

The standard mortar joint thickness is 10 mm for both bed joints (horizontal) and perpend joints (vertical). Joints of 6–8 mm are used in face brickwork where a neater finish is needed. Joints thicker than 12–15 mm weaken the overall wall and are generally avoided except when using irregular handmade bricks.

Allow a minimum of 10% wastage for bricks. This covers breakage during delivery, cutting around openings, chasing for pipes and cables, and end-of-batch off-cuts. For walls with many openings, curved or angled sections or decorative patterns increase this to 15–20%. It is always cheaper to buy too many than to have a shortfall from a different batch that may not match in colour.

A 1:4 cement:sand mix is the most widely recommended mortar for external walls in exposed locations. For very severe exposure — coastal areas, parapets, retaining walls — use 1:3. For sheltered external walls a 1:5 mix is acceptable. Always match the mortar strength to the brick: do not use a strong mix with soft or reclaimed bricks as it can cause spalling in freeze-thaw conditions.

Brick & Mortar Calculator

Brick Bonding and Wall Thickness

What Mortar Mix Should I Use?

Frequently Asked Questions