Concrete Block Calculator (CMU Wall)
Enter the wall size and any openings.
Your numbers
%
Your results
Blocks needed
Blocks needed
—
Wall area (sq ft)
—
Blocks per course
—
Courses
—
Concrete Block Calculator (CMU Wall) by TheCalcTools
How the Concrete Block Calculator (CMU Wall) works
A standard concrete masonry unit is 15⅝ × 7⅝ inches on its face; with a ⅜-inch mortar joint it covers 16 × 8 inches, 0.889 sq ft. Wall area ÷ 0.889 gives the block count.
Corners, bond beams and openings need special units; reinforced walls need grout and rebar as designed.
The formula
Blocks = area ÷ 0.889 sq ft × (1 + waste)
Worked example
Using the default values shown in the calculator:
| Wall length (ft) | 40 |
|---|---|
| Wall height (ft) | 6 |
| Openings (sq ft) | 0 |
| Waste | 5 % |
- A 40 × 6 ft wall: 240 sq ft, 284 blocks with 5% waste.
Result:
| Blocks needed | 284 |
|---|---|
| Wall area (sq ft) | 240 |
| Blocks per course | 30 |
| Courses | 9 |
Frequently asked questions
How many blocks per square foot?
1.125 blocks per square foot for standard 8 × 16 units.
Sources and further reading
Related calculators
More in Construction & DIY · All calculators
This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.