Brick and Mortar Calculator

How many bricks do I need?

Multiply wall length by wall height, subtract openings, then divide by the brick face area including the mortar joint. For a double-skin wall, double the net wall area before calculating. Add 5% to 10% waste for cuts, breakage, and site handling.

How many bricks per square metre?

A standard UK brick measuring 215 x 102.5 x 65 mm with a 10 mm mortar joint uses about 59 bricks per m² for a single-skin wall before waste. A double-skin wall uses about 118 bricks per m² before waste.

How many bricks per square foot?

A US modular brick measuring 7.5 x 3.5 x 2.25 in with a 3/8 in mortar joint uses about 6.8 bricks per square foot before waste. Larger king bricks need fewer bricks per square foot because each brick covers more face area.

How much mortar do I need for 1000 bricks?

As a rough guide, 1000 standard UK bricks usually need about 0.25 to 0.30 m³ of wet mortar, depending on joint thickness, brick frogs/perforations, wastage, and workmanship. For US modular brickwork, 1000 bricks often need about 10 to 12 cu ft of mortar. Use the calculator for a project estimate based on your selected brick size and joint thickness.

How many bags of mortar do I need?

Divide the estimated mortar volume by the yield per bag. For example, if the wall needs 0.28 m³ of mortar and each 25 kg bag yields about 0.014 m³, you need about 20 bags. If an 80 lb bag yields about 0.60 cu ft, divide total cubic feet by 0.60.

Single skin vs double skin brick walls

A single-skin wall has one layer of brickwork, often used for garden walls, veneers, and non-structural masonry. A double-skin wall has two masonry leaves, so it usually needs roughly twice the bricks and more mortar for the same visible wall area.

Standard brick sizes: UK and US

The common UK brick size is 215 x 102.5 x 65 mm, normally used with a 10 mm mortar joint. Common US sizes include modular brick at 7.5 x 3.5 x 2.25 in, standard brick at 8 x 3.75 x 2.25 in, and king brick at 9.5 x 3.5 x 2.75 in.

How to subtract windows and doors

Find each opening area by multiplying its width by its height, add the opening areas together, then enter that total in the openings field. The calculator subtracts this from the gross wall area before estimating bricks, blocks, mortar, sand, cement, and cost.

Brick wall cost estimate

The cost estimate adds brick or block cost plus mortar bag cost. Enter a unit price for each brick or block and a price per mortar bag. Labour, delivery, lintels, ties, reinforcement, damp-proof course, waste disposal, and VAT or sales tax are not included unless you add them separately.

Explanation

Brick quantity estimates start with the measured wall length and height. The calculator multiplies those dimensions to get gross wall area, subtracts window and door openings, then applies single-skin or double-skin wall type before estimating bricks or blocks. If you already know the wall area, use the alternate wall area input instead of length and height.

Each brick occupies a face area that includes the mortar joint. A thicker joint increases the effective brick footprint and reduces the number of bricks per square unit. The calculator adds the selected joint thickness to the brick length and height, then uses that modular face size to estimate the units required. A waste factor accounts for cuts, breakage, and layout adjustments on the job site.

Mortar volume is based on the difference between the masonry wall volume and the volume occupied by the installed bricks or blocks. The result is converted into mortar bags using the selected bag yield, and the sand and cement estimate uses a common 1:4 cement-to-sand mortar ratio by volume. Because mortar yield, compaction, moisture, and mix type vary, always confirm product labels and local specification requirements.

If your project includes corners, piers, or special bond patterns, brick usage may increase beyond a simple area calculation. Mortar volume can also shift with recessed joints, raked joints, or wider head joints. Consider adding an extra margin when ordering, especially for projects with numerous openings or decorative details that require additional cuts.

Formula

Gross wall area: Agross = wall length x wall height

Net wall area: Anet = Agross - openings

Takeoff area: Atakeoff = Anet x wall skin factor

Modular face size: Lm = L + J, Hm = H + J

Bricks or blocks: units = Atakeoff / (Lm x Hm), plus waste

Mortar volume: Vmortar = wall volume - installed units x unit volume

Example Calculation

For a 5 m by 2.4 m single-skin UK wall with no openings, standard 215 x 102.5 x 65 mm bricks, a 10 mm mortar joint, and 5% waste, the calculator estimates the required bricks, mortar volume, 25 kg mortar bags, and approximate sand and cement quantities. Add opening area when the wall includes windows or doors.

UK brick calculator: standard 215 x 102.5 x 65 mm brick

UK projects commonly use metric wall measurements, a 10 mm mortar joint, standard 215 x 102.5 x 65 mm bricks, and 25 kg bag assumptions. In metric mode, this calculator shows millimetre brick dimensions, defaults the joint to 10 mm, and reports wall area in square metres.

How many bricks per m²?

A standard UK brick with a 10 mm joint has a nominal face of 225 x 75 mm, so a single-skin wall uses about 59 bricks per m² before waste. Double-skin walls need roughly twice that amount.

US brick calculator: modular, standard, and king brick sizes

US projects often use feet, square feet, inch-based brick dimensions, a 3/8 inch mortar joint, and 80 lb mortar bag assumptions. In imperial mode, the brick selector switches to inch labels and the joint default changes to 0.375 in.

How many bricks per square foot?

A US modular brick with a 3/8 inch joint usually works out to about 6.8 bricks per square foot before waste. Standard and king brick counts vary because their face dimensions are different.

FAQs

Can I enter wall length and height instead of wall area?

Yes. Length and height are the primary inputs. Use alternate wall area only when you already know the area.

Does this subtract windows and doors?

Yes. Enter total opening area and the calculator subtracts it before estimating materials.

What is the difference between single-skin and double-skin?

A double-skin wall has two masonry leaves, so the calculator doubles the takeoff area for brick and mortar estimates.

Why does joint thickness change brick count?

The joint adds to the effective brick size, so each brick covers more area as the joint grows.

Can I use this for veneer walls?

Yes, just use the veneer area and a single-wythe thickness. Add substrate and ties separately.

How do I estimate mortar mix type?

This calculator only estimates volume. Mix type depends on exposure and structural requirements.

Should I add extra bricks for cuts?

Yes. Use the waste factor to cover breakage, cuts, and site adjustments.

Does this include flashing or reinforcement?

No. Those components should be accounted for in the project specification.

How it works

This tool uses modular brick geometry and mortar joint thickness to estimate brick count and mortar volume. All calculations run client-side.

Disclaimer

This is a material estimator only. Verify structural requirements, reinforcement, and local codes for masonry construction.