Wall Dimensions
440 × 215 × 100mm (standard hollow)
Add 5% for breakages
Subtract area for doors and windows
Results
Enter dimensions and click Calculate to see results
NAIBC / IRC codes
References & Sources
Standards Cited
- ASTM C90 — Standard Specification for Loadbearing Concrete Masonry Units
Defines standard CMU dimensions (8x8x16 in, 4x8x16 in, 12x8x16 in) and tolerances used in the calculator - TMS 402/602 — Building Code Requirements and Specification for Masonry Structures
Design rules for CMU blockwork including mortar joint specifications and structural requirements
Formulas Used
- Blocks per m2:
blocksPerM2 = 1 / ((blockLength + mortarJoint) x (blockHeight + mortarJoint))
Source: ASTM C90 / TMS 402/602 — Standard 440x215mm block with 10mm joints gives approximately 10 blocks per m2 - Total blocks:
totalBlocks = ceil(netWallArea x blocksPerM2 x (1 + wastage/100))
Source: Standard quantity surveying method
Key Assumptions
- Standard CMU: 406 x 203 x 203mm (8x8x16 in); half block: 406 x 203 x 102mm; large: 406 x 203 x 305mm — ASTM C90
- Default mortar joint width: 10mm (3/8 in) — TMS 402/602
- Typical wastage allowance of 5% for cutting and breakage — Industry standard practice