Home & Construction⏱ 5 min read
How to Calculate Bricks and Mortar for Any Wall
One of the most common DIY miscalculations. Here's the exact formula for standard UK bricks, mortar quantities, and how to handle corners, openings, and different bond patterns.
Running short of bricks mid-project is an expensive mistake — a second delivery costs extra, and a new batch may not match perfectly. Here's how to calculate precisely every time.
Standard UK Brick Dimensions
Standard UK brick: 215mm x 102.5mm x 65mm (L x W x H)
Mortar joint: typically 10mm
With mortar, each brick occupies:
225mm x 112.5mm x 75mm (including half a joint each side)
Bricks per m2 (single skin, stretcher bond):
1,000 / (22.5 x 7.5) = 1,000 / 168.75 = 5.93 bricks
Round up: 60 bricks per m2
Bricks Per m2 by Bond Pattern
Bond PatternBricks per m2Notes
Stretcher bond (half brick wall)60Most common for single-skin walls
English bond (full brick)120Strongest, alternating header/stretcher courses
Flemish bond (full brick)120Decorative, alternate headers in each course
English garden wall bond903 stretcher courses per header course
Calculating Total Bricks
Step 1: Calculate gross wall area
Wall: 6m long x 1.8m high = 10.8 m2
Step 2: Deduct openings
Gate opening: 1.2m x 1.8m = 2.16 m2
Net area: 10.8 - 2.16 = 8.64 m2
Step 3: Multiply by bricks per m2
Stretcher bond: 8.64 x 60 = 518 bricks
Step 4: Add 10% waste (cuts, breakages, rejects)
518 x 1.10 = 570 bricks → order 600 (standard pack sizes)
Mortar Quantities
Standard mix: 1 part cement : 4 parts building sand (by volume)
Mortar volume per 1,000 bricks: approximately 0.7 m3
For 570 bricks: 0.7 x (570/1000) = 0.40 m3 mortar
Materials for 0.40 m3 of 1:4 mortar:
Total mix = cement + sand = 5 parts
Cement: 0.40 / 5 = 0.08 m3 ≈ 100 kg (2 x 50kg bags)
Sand: 0.40 x 4/5 = 0.32 m3 ≈ 500 kg (half a tonne bag)
Ready-mixed mortar (tubs) — easier for small jobs:
1 tub (25kg) covers approximately 100 bricks
Estimating Courses for a Given Height
Courses = Wall height (mm) / 75mm (brick + joint height)
1.8m (1800mm) wall: 1800 / 75 = 24 courses
1.0m wall: 1000 / 75 = 13.3 → 14 courses (round up)
Checking: does your desired height divide neatly into 75mm?
1,800mm = exactly 24 courses ✓
1,500mm = exactly 20 courses ✓
1,350mm = exactly 18 courses ✓
Choose heights that avoid awkward half-courses.