Brick & Block Calculator

How to use it: enter the wall's length and height, the face dimensions of the brick or block you're laying, the mortar joint thickness, and a waste allowance for cuts and breakage. The result updates immediately.

Formula. Each unit in the wall face occupies its own footprint plus one mortar joint on each side it shares with a neighbour, so the effective unit size is brick length + joint by brick height + joint. Dividing wall area by that effective footprint gives the unit count, then waste is added on top:

units = ceil( (wall length × wall height) ÷ ((brick length + joint) × (brick height + joint)) × (1 + waste% ÷ 100) )

Worked example. With the defaults above (8 m × 2.4 m wall, 215 × 65 mm brick, 10 mm joint, 5% waste): effective unit size is 225 mm × 75 mm = 16,875 mm² per unit. Wall area is 8000 mm × 2400 mm = 19,200,000 mm², i.e. 19.2 m². 19,200,000 ÷ 16,875 ≈ 1137.78 bricks before waste; × 1.05 ≈ 1194.67, rounded up to 1195 bricks, or about 59.3 bricks per m².

The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.

Wall length

8 m

Wall height

2.4 m

Brick/block length

215 mm

Brick/block height

65 mm

Mortar joint

10 mm

Waste allowance

5 %

Primary result: Units needed: 1195.

• Measure from the datum or reference edge described by this tool, and do not mix inside, outside and centerline dimensions.
• Keep inputs in the displayed units and preserve more precision than the final cutting or purchasing tolerance requires.
• When the result is close to a limit, verify it with a test piece, field measurement, manufacturer drawing or qualified project professional.

This calculator treats the wall as one solid rectangle - it does not deduct door or window openings. Work out opening area separately and subtract it from wall area (or reduce wall length/height) before comparing against a supplier quote.

It assumes a simple layout with uniform joints in both directions. It does not account for cut units at corners and ends, header/soldier courses, bond patterns that waste more material, piers, or reinforcement pockets - all of which typically need extra units beyond the waste percentage entered here.

Brick and block face sizes vary widely by region and product line - the 215 × 65 mm default is a common metric brick size, but always check the actual dimensions of the unit you're buying.