Concrete Block Calculator
Estimate how many concrete blocks you need for a wall — pick block size, add waste, get a count.
Estimates are for planning purposes only. Verify quantities with your supplier and a qualified professional before ordering.
How it works
- 1Enter the wall length and height in metres or feet using the Metric/Imperial toggle.
- 2Select your block size — Standard 440×215 mm, US CMU 16×8 in, or Jumbo 440×290 mm (face areas include a 10 mm joint).
- 3Set a waste percentage to account for cuts and breakages; the calculator rounds up to the nearest whole block.
Use cases
- Estimating materials before placing a bulk order for a garden or boundary wall.
- Comparing how block size affects total count and cost across standard, CMU, and jumbo formats.
- Quick on-site checks to confirm remaining stock is sufficient.
Frequently asked questions
How many standard concrete blocks cover 1 m²?
A standard 440×215 mm block with a 10 mm joint covers 0.10125 m², so you need about 9.88 blocks — rounded up to 10 per m². Add 5–10% for cuts and waste.
Why does the calculator round up?
You cannot buy a fraction of a block, and partial blocks are wasted during cuts. The formula is ⌈(area ÷ block face area) × (1 + waste/100)⌉, so you always order enough.
What waste percentage should I use?
For straight walls with few openings, 5% is typical. Add 10–15% for walls with many windows, doors, or complex corners where more cutting is involved.
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