Free Block Quantity calculator with clear step-by-step results.
A block wall is counted by area, not by length. The face area of one block including its mortar joint tells you how many blocks cover a square metre, and multiplying that by the wall area gives the net count. A 440 × 215 mm block on a 10 mm joint covers 0.0765 m², so roughly 13 blocks fill each square metre. Cutting waste is added on top because every corner, opening and course end produces an off-cut you cannot reuse.
Blocks per square metre
Blocks/m² = 1 ÷ ((block length + joint) × (block height + joint))
Order quantity
Blocks to order = ceil(wall area × blocks/m² × (1 + waste))
A material take-off is not a structural design. Wall thickness, block strength, reinforcement and foundations must be specified by a qualified engineer and comply with your local building code.
The block occupies its own face area plus half a joint on each side, so the repeating module is the block plus one full joint in each direction. Ignoring the joint over-orders by roughly 8-10% on a standard block.
5% suits a plain rectangular wall. Allow 8-10% where there are many openings, piers or angled cuts, because each cut block usually yields only one usable piece.
No — it returns the block count only. Mortar, wall ties, reinforcement and fill are separate take-offs.