Concrete block calculator
Concrete blocks 40×20 cm (≈12.5 pcs/m² with 1 cm joint).
Purchase quantity
262.5 unit
Net measurement: 250 unit · Waste 5 %
- Net blocks250 unit
- Blocks to buy262.5 unit
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Shopping list
What to buy for this calculation. Look up each material at your store.
- Blocks to buy · 262.5 unitSearch at Amazon
How it's calculated (visible formula)
pcs = area × 12.5; buy = pcs × (1+waste)
- Net geometric measurement, no waste.
- Adjustable waste % for cuts and breakage.
- Purchase rounded up to sellable units (boxes, bags, buckets, boards).
Worked example: 20 m² wall
- 20 × 12.5 = 250 pcs
- +5% → 262.5
→ 263 blocks.
Common mistakes
- Missing half blocks and closer units.
- Forgetting mortar (use the mortar calculator).
From calculation to quote
Add labour, overhead and your margin, and generate the professional PDF.
FAQs
- 150 or 200 mm block?
- Same pcs/m² for equal length/height; thickness and mortar use change.
- How many 16×8 in blocks per square foot?
- About 1.1–1.2 pcs/sq ft with a 3/8 in joint. Confirm with your block.
- How many blocks per square foot?
- At 12.5 pcs/m² that's about 1.2 blocks per sq ft before waste. Switch to Imperial to enter feet and inches.
- Is mortar separate?
- Yes: blocks exclude mortar. Estimate it with the mortar calculator.
Maintained by Srikanta M · Formula v1.0.0 · Verified 2026-09-10 · Updated 2026-09-10 · Limits: quantity estimation, not structural design or site supervision.