Block Calculator
Work out how many blocks you need for a wall.
Blocks required
143blocks
- Wall area
- 14.4 m²
Includes 10 mm mortar joints.
v1.0 · Reviewed September 2026
How this is worked out
Each block is treated as its face size plus a 10 mm joint on the length and the height. The wall area is divided by that coordinating size, multiplied by any waste allowance, then rounded up.
Worked example
- Wall 6 m × 2.4 m
- Block 440 × 215 mm
- No waste allowance
14.4 m² ÷ (0.45 × 0.225) = 142.2, rounded up
143 blocks
Assumptions and limits
- Single skin only. A cavity wall needs the calculation running for each leaf.
- Openings are not deducted and cutting waste is not added unless you enter an allowance.