Concrete Block Calculator
Estimate concrete blocks (CMU) and mortar for any wall.
Use this concrete block calculator to estimate the number of concrete masonry units (CMU) and mortar bags needed for any wall. Enter the wall dimensions and waste percentage to calculate materials using the face area of a standard 8×8×16 CMU.
Blocks needed
190
incl. 5% waste
Mortar bags
7
70 lb type S
Wall area
160
ft²
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Recommended tools & materials
Handy picks for this project on Amazon.
Brick Trowel
Spread mortar quickly and evenly
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Type S Mortar Mix
For block, brick and retaining walls
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Mason's Line & Line Blocks
Keep every course straight
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4 ft Masonry Level
Check plumb and level as you build
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How does the concrete block calculator work?
A standard 8×8×16 CMU covers 0.888 ft² of face (128 in² ÷ 144). Divide wall area by that number to get block count.
Formula: blocks = (L × H) ÷ 0.888 × (1 + waste%)
Which guide explains this in more depth?
- How inspectors check brick and mortar counts on a single-wythe wall. Read the inspector-approved brick calculator method guide for the full worked example.
What else do people ask about this calculator?
How many concrete blocks in a 10×10 wall?
A 10 ft × 10 ft wall is 100 ft², so ~113 8×8×16 blocks plus about 4 bags of mortar.
How many blocks in a bag of mortar?
About 30 CMU blocks per 70 lb bag of type S mortar.
Which related calculators should I use next?
Where can I learn more about these materials?
Weights, coverage, types and buying tips for the materials this calculator estimates.
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