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HeizerDesk Concrete Block Calculator
Standard CMU covers 8 by 16 inches face, so a square foot of wall takes 1.125 blocks. Enter the wall and this returns block, mortar and core-fill volume. This is a free Concrete Block Calculator — no sign-up, and the arithmetic is written out below so you can check it.
Your numbers
Result
Blocks to order
378
blocks
- Mortar bags~28 blocks per 80 lb bag
- 14bags
- Courses high
- 12courses
- Cores to grout
- 16cores
- Grout volume
- 1.99cubic yards
- Vertical rebar
- 128linear ft
- Net wall area
- 320sq ft
How this is calculated
- A nominal 8×16 in block face covers 0.888 sq ft, so a square foot of wall takes 1.125 blocks.
- Courses = wall height in inches ÷ 8, since a block plus its joint is 8 in tall.
- Grout ≈ 0.28 cubic feet per core per course for a standard 8 in block.
Before you order
- Block count per square foot is the same for 4, 8 and 12 inch block — the face is identical, only the thickness changes. Weight, cost and grout volume are not the same.
- Reinforcement spacing and which cores get filled are engineering decisions, especially for a retaining or load-bearing wall. This counts material, it does not design the wall.
- Bond beams at the top and over openings need their own block and steel and are not included here.