Brick, Block & Retaining Wall Calculator
Estimate bricks, concrete blocks or retaining wall blocks for a wall of any size — with openings, mortar joints and waste.
How to use
- 1Enter the wall length and height and any openings.
- 2Choose the unit type or enter a custom face size.
How it's calculated
Units = net wall area ÷ ((unit length + joint) × (unit height + joint)) × (1 + waste). US modular brick 7⅝ × 2¼ in with ⅜ in joints ≈ 6.75 per ft²; 8 × 16 in block ≈ 1.125 per ft².
Frequently asked questions
How many bricks per square foot?
About 6.75 US modular bricks per square foot of single-wythe wall with 3/8 in joints; about 60 per m² for UK/EU standard bricks.
Do retaining walls need a base?
Yes — typically 6 in of compacted gravel, with the first course partly buried. Walls over about 3–4 ft usually need engineering.
How much waste should I add?
About 5% for plain walls and 10% where there are many cuts or corners.