Calculate the number of concrete masonry units (CMU) or cinder blocks needed for your wall or foundation project. Enter wall dimensions to get block counts, mortar estimates, and rebar requirements for standard 8-inch or 12-inch blocks.
Enter Your Measurements
Results
Blocks Needed (with waste)
371
blocks
Blocks (exact)
337
blocks
Wall Area
320
sq ft
Courses (rows)
12
courses
Mortar (80 lb bags)
29
bags
Formula
How to Use This Calculator
How to Use
- 1
Enter the total wall length in feet.
- 2
Enter the wall height in feet.
- 3
Enter the block dimensions (standard CMU is 16 in × 8 in × 8 in nominal).
- 4
Adjust the waste factor as needed.
Frequently Asked Questions
Frequently Asked Questions
How many concrete blocks per square foot?
How many bags of mortar per block?
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About This Calculator
This calculator uses the formula: Blocks per Sq Ft = 1 ÷ ((Block Length + 3/8) ÷ 12 × (Block Height + 3/8) ÷ 12) | Total = Wall Area × Blocks per Sq Ft. All calculations follow industry-standard methods. Results are estimates — always verify with a licensed professional for structural or code-compliant work.
Built and maintained by the CalcSmart team. Last updated March 2026.
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