Brick Calculator: How Many Bricks for a Wall

Brick Calculator: How Many Bricks You Need for a Wall

A brick calculator estimates how many bricks a wall requires, based on its height, width and thickness. It accounts for the mortar joints between bricks, so the result matches how a bricklayer actually builds the wall rather than a simple area estimate.

Material costs make up a large share of a masonry project's budget. Ordering too few bricks means a delayed delivery and possible colour mismatch between batches. Ordering too many wastes money and storage space. A correct count avoids both problems.

How to Calculate Bricks Needed for a Wall

A brick wall is built from one or more skins (also called wythes). A skin is a single brick-thick layer. A half-brick wall has one skin; a full-brick wall has two skins joined by a mortar collar joint.

Mortar sits between bricks along a course (the horizontal "bed joint") and between bricks within a course (the vertical "perpend joint"). It does not sit across the width of a single skin, because the brick itself already fills that space. The calculation works in two stages: how many bricks cover one square metre of wall face, and how many skins deep the wall is.

1. Wall area $\text{Wall Area} = \text{Height} \times \text{Width}$

2. Bricks per square metre of one skin $\text{Bricks per m}^2 = \frac{1}{(\text{Brick Length} + \text{Mortar}) \times (\text{Brick Height} + \text{Mortar})}$

3. Number of skins $\text{Skins} = \text{round}\left(\frac{\text{Wall Thickness} + \text{Mortar}}{\text{Brick Width} + \text{Mortar}}\right)$

   The calculator always counts at least one skin.

4. Total bricks $\text{Bricks Needed} = \text{Skins} \times \text{ceil}(\text{Wall Area} \times \text{Bricks per m}^2)$

The result is rounded up, because a fraction of a brick cannot be ordered.

This calculator always uses the standard UK brick size (215 mm × 102.5 mm × 65 mm with a nominal 10 mm mortar joint); it does not accept custom brick dimensions. With those figures, one skin covers about 59.3 bricks per square metre, commonly rounded to 60 bricks per m². A two-skin (full-brick) wall needs about 120 bricks per m².

Standard Brick Dimensions by Region

Brick sizes vary by country. The table below is for reference only. This calculator's formula is fixed to the UK size.

With its 10 mm joint, a UK brick takes up 225 mm × 112.5 mm × 75 mm of wall. A US modular brick has a specified size of 7⅝ in × 3⅝ in × 2¼ in (194 mm × 92 mm × 57 mm), laid with a ⅜ in (9.5 mm) or ½ in (12.7 mm) joint.

Worked Example

A garden boundary wall has these dimensions:

• Height: 1.8 m
• Length: 10 m
• Thickness: 0.215 m (a two-skin, "one-brick" wall)

Step by step:

1. Wall area = 1.8 × 10 = 18 m²
2. Bricks per m² of one skin = 1 ÷ (0.225 × 0.075) = 59.26
3. Bricks for one skin = ceil(18 × 59.26) = ceil(1,066.7) = 1,067
4. Skins = round(0.225 ÷ 0.1125) = round(2.0) = 2
5. Total bricks = 2 × 1,067 = 2,134 bricks

Adding a 5% waste allowance: 2,134 × 1.05 = 2,240.7, rounded up to 2,241 bricks. It is worth checking the supplier's pack size, since bricks are usually sold in fixed-quantity packs rather than single units.

Adding a Waste Allowance

Bricks break in transit, get cut wrong, or turn out defective. A calculator result is the minimum needed, not the amount to order. The Brick Industry Association's estimating guide adds at least 5 percent for breakage and waste. Particular job conditions, such as many cuts or a curved wall, may call for more.

$\text{Total with Waste} = \text{Bricks Needed} \times (1 + \text{Waste Factor})$

Accounting for Doors and Windows

Two approaches work. First, calculate the full wall, then subtract the opening: estimate the opening's area, convert it to a brick count using the same bricks-per-m² and skins figures, and subtract that from the total. Second, calculate each solid section of wall around the opening separately and add the results together. The second method is more reliable for walls with several openings.

Brick Bond and Extra Material

The bond is the pattern bricks are laid in. It changes how many bricks show on the face of the wall:

• Running (stretcher) bond: each brick overlaps the joint below it, and only the long faces show. The calculator's figure applies directly.
• English bond: rows of headers (brick ends) alternate with rows of stretchers (brick faces).
• Flemish bond: headers and stretchers alternate within each row.

Headers turn a brick sideways, so it covers less face area. When estimating a face wythe in a bond with headers, the Brick Industry Association adds one-half more bricks for English bond and one-third more for Flemish bond to the running-bond count. In a solid two-skin wall each header fills space in both skins, so the calculator's two-skin total already covers them.

Frequently Asked Questions

How accurate is the brick calculator?

The arithmetic is exact for the standard UK brick size it uses. Real-world variation comes from brick size tolerances, mortar joint thickness and cutting waste, which is why a waste allowance of at least 5% is added to the raw count.

Does the calculator include mortar?

Yes. It treats the mortar joints between bricks (bed and perpend joints) as part of the spacing, but not as an extra layer across the thickness of a skin, since a brick already occupies that space.

How many bricks are in one square metre?

For a standard UK brick with a 10 mm joint: about 60 bricks per m² for a single-skin (half-brick) wall, and about 120 bricks per m² for a two-skin (full-brick) wall. This is a useful sanity check on any result.

What is a skin (wythe) in brickwork?

A skin is one brick-thick layer of a wall. A half-brick wall (102.5 mm) has one skin. A full-brick wall (215 mm) has two skins joined by a mortar collar joint.

Should extra bricks be ordered for waste?

Yes. Add at least 5% for breakage and waste, and more for work with many cuts or curves. Ordering everything in one batch also avoids visible colour differences between manufacturing runs.

Does it work for a cavity wall?

Not directly. The calculator treats the thickness as solid brickwork, so the air gap in a cavity wall would be counted as extra skins. Run it once for each skin at 0.1025 m thickness and add the two results.

Can the calculator be used for non-UK brick sizes?

Not directly. It is fixed to the UK standard size (215 × 102.5 × 65 mm) with a 10 mm joint. For a different brick size, measure the actual brick, add the mortar joint thickness to each dimension, and recompute the bricks-per-m² figure by hand using the formula above.

References

1. Brick Development Association. Designing to Brickwork Dimensions (technical guide, 2023). Designing to Brickwork Dimensions — UK work size 215 × 102.5 × 65 mm, nominal 10 mm joint, co-ordinating size 225 × 112.5 × 75 mm.
2. Brick Industry Association. Technical Note 10: Dimensioning and Estimating Brick Masonry. TN 10: Dimensioning and Estimating Brick Masonry — US modular brick 3⅝ × 2¼ × 7⅝ in with ⅜ or ½ in joints; at least 5 percent waste; bond correction factors (English ½, Flemish ⅓).