Brick Calculator – Bricks and Mortar for a Wall

Estimate Bricks and Mortar for a Wall

Wall length

Wall height

Openings to subtract

Brick size

Mortar joint thickness

US practice: 3/8 in. UK practice: 10 mm (= 0.394 in).

Wall type

Waste allowance

Covers cut bricks at openings, corners and breakage.

Mortar bags per 1,000 bricks

bags

≈ 7 × 80 lb bags per 1,000 modular bricks typical; adjust to your mix.

Price per brick

Optional. Clear this field to omit the cost estimate.

Calculate automaticallyIf enabled, the result will update automatically when you change any value.

Brick & Mortar Estimate

Net wall area after openings

Bricks per square foot

Bricks needed (before waste)

Bricks to buy (incl. waste)

Mortar bags (80 lb)

Estimated brick cost

Calculation notes

Brick

Formula

\[ A = L \times H - \sum_{i=1}^{n} w_i \times h_i \] \[ p = \frac{144}{(b_L + j)(b_H + j)} \] \[ N = \lceil A \times p \times W \times (1 + \tfrac{\%}{100}) \rceil \]

Where:

$A$ — net wall area after subtracting openings (ft²)
$L$, $H$ — wall length and height
$w_i$, $h_i$ — width and height of each opening (door or window)
$p$ — bricks per square foot
$b_L$, $b_H$ — brick face length and height (inches)
$j$ — mortar joint thickness (inches)
$W$ — number of wythes (wall layers: 1 or 2)
$N$ — number of bricks to buy, including the waste allowance and rounded up

Gross wall area is length times height; the areas of all openings are subtracted from it. The brick density converts the net area into a brick count: each brick plus one mortar joint occupies a small rectangle, and 144 (the number of square inches in a square foot) divided by that rectangle gives the bricks needed per square foot.

Brick – Calculation Example

Example: a 30 ft long, 10 ft high wall with one 3 ft × 5 ft window, built from US modular bricks (7⅝ × 2¼ in) with 3/8 in mortar joints, single wythe, and a 5% waste allowance.

\[ A = 30 \times 10 - 3 \times 5 = 285\ \text{ft}^2 \]

\[ p = \frac{144}{(7.625 + 0.375)(2.25 + 0.375)} = \frac{144}{8 \times 2.625} \approx 6.86 \ \text{bricks/ft}^2 \]

\[ N = \lceil 285 \times 6.857 \times 1.05 \rceil = \lceil 2052.0 \rceil = 2052 \]

Result: about 1,954 bricks before waste, 2,052 bricks to buy, and at 7 bags per 1,000 bricks, 15 × 80 lb bags of mortar. At $0.55 per brick, the brick cost is $1,128.60.

How to use the brick calculator

Enter the Wall length and Wall height and choose ft or m for each unit.
Select how many Openings to subtract (doors and windows). If you choose more than “None”, enter each opening’s width and height and pick the shared Opening unit (ft, in, or m).
Pick a Brick size: US modular 7⅝ × 2¼ in, US standard 8 × 2¼ in, UK 215 × 65 mm, or Custom size. For a custom brick, enter the face length and height in inches or millimetres.
Enter the Mortar joint thickness — 3/8 in is typical in the US, 10 mm in the UK.
Choose the Wall type: single wythe (one layer of bricks) or double wythe (two layers).
Set the Waste allowance (5–10% is common) and, optionally, Mortar bags per 1,000 bricks and Price per brick to get a cost estimate.
Read the results: net wall area, bricks per ft², the number of bricks to buy, mortar bags, and estimated cost.

What the brick calculator does

This calculator estimates the number of bricks needed to build a wall based on its dimensions, the brick size, and the mortar joint. It subtracts windows and doors, adds a waste allowance, and converts everything into practical purchase quantities: bricks, bags of mortar, and — if you enter a price — the material cost.

The key step is the brick density, bricks per square foot. A brick laid on the wall occupies its face length and height plus half a mortar joint on each exposed side — in practice the joint is added to both dimensions. Dividing 144 square inches by the area of this brick-plus-joint rectangle gives how many bricks cover one square foot. For a US modular brick with 3/8 in joints that is about 6.86 bricks per ft²; for a UK standard brick with 10 mm joints it is about 60 bricks per m².

The two result counts answer different questions. “Bricks needed (before waste)” is the theoretical count from geometry alone. “Bricks to buy (incl. waste)” adds your waste allowance and rounds up to a whole number — this is the figure to order. Cuts at openings and corners, damaged bricks, and colour-matching across batches all make some surplus essential.

The mortar result uses the classic rule of thumb of about seven 80 lb bags of premixed mortar per 1,000 modular bricks. If you are mixing your own from masonry cement and sand, or using larger or smaller bricks, adjust the rate — the Sand calculator can help you estimate the sand volume for a custom mix.

Assumptions, limitations and tips

The calculator assumes a running bond pattern with bricks laid on their faces. Flemish bond, herringbone, and other decorative patterns use more bricks because of extra cuts.
Only the wall face is counted. A double wythe (two layers) doubles the count, but piers, columns, and footings need to be estimated separately.
Openings are subtracted as simple rectangles. In reality, a lintel and extra cuts around each opening use additional bricks, which the waste allowance should cover.
A 5% waste allowance suits simple, rectangular walls; use 10% or more for walls with many openings, intricate details, or thin mortar joints, where more bricks end in cuts.
Bricks are sold in cube or pack quantities, so round up to the nearest pack when ordering. Mortar estimates vary with joint thickness, brick absorption, and mix design, so treat the bag count as a planning figure.
The cost estimate covers bricks only. Mortar, sand, wall ties, lintels, flashing, and labour are extra — for other materials in the project, see the Square Footage calculator and the Drywall calculator for interior finishes.
Check local building codes before building: many regions require minimum wall thickness, ties, and reinforcement for brick walls.

Frequently Asked Questions

How many bricks are in a square foot of wall?

It depends on the brick size and mortar joint. For a US modular brick (7⅝ × 2¼ in) with 3/8 in joints: $p = \frac{144}{(7.625+0.375)\times(2.25+0.375)} \approx 6.86$ bricks per ft². A US standard 8 × 2¼ in brick gives about 6.55 per ft², and a UK brick with 10 mm joints gives roughly 60 per m² (about 5.6 per ft²).

How do I calculate the number of bricks for a wall without a calculator?

Multiply wall length by height to get the gross area, subtract the area of any doors and windows, and multiply by the bricks per square foot for your brick. For example, a 10 ft × 10 ft wall with US modular bricks needs about $100 \times 6.86 \approx 686$ bricks before waste. Then add 5–10% for cuts and breakage — that is the number to order.

How many bricks do I need per m² in the UK?

A standard UK brick (215 × 65 mm) with 10 mm mortar joints covers 225 × 75 mm, so $p = \frac{1{,}000{,}000}{225 \times 75} \approx 59.3$, commonly quoted as 60 bricks per m². A double-skin (cavity) wall of two brick wythes therefore uses about 120 bricks per m². Order 5–10% extra for cuts and damaged bricks, especially around openings.

How many bricks do I need to build a house?

Estimate each wall separately: multiply length by height, deduct windows and doors, and multiply by bricks per ft² (or per m²). Add up all exterior and interior brick walls, then add 5–10% waste. As a rough guide, a typical US brick veneer home with about 2,000 ft² of wall needs 13,000–15,000 modular bricks. Foundations, piers, and chimneys must be counted separately, and local codes may mandate wall thickness and reinforcement.

Why doesn't my mortar bag estimate match the brick count I expected?

The default of seven 80 lb bags per 1,000 bricks fits US modular bricks with 3/8 in joints. Larger bricks, thinner joints, high-absorption bricks, or a rich custom mix all change the rate — thin 1/4 in joints can drop it to about 6 bags per 1,000, while heavier clay bricks may need more. Treat the bag count as a planning figure and buy a little extra; leftover mortar is cheaper than a mid-job shortage.

Can I use this calculator for a brick patio or walkway instead of a wall?

Yes, with adjustments. Enter the paved area as length × height with no openings, choose single wythe, and select your paver as a custom size. Because pavers are usually laid with tight 1/8–1/4 in joints, enter a small joint thickness — the field will not accept a joint larger than the brick. Note that sand bedding and edge restraints replace mortar, so ignore the mortar bag result for dry-laid paver projects.

What waste allowance should I use, and do I really need extra bricks?

Always order extra. A 5% allowance suits simple, rectangular walls; use 10% or more for walls with many openings, corners, decorative patterns like herringbone, or thin joints that force more cuts. Surplus also covers bricks broken in delivery and future repairs — matching colour later is hard because brick tones vary between batches. Since bricks are sold in cubes or packs, round the final figure up to the nearest pack size when ordering.