Concrete Block Calculator
Calculate the number of concrete blocks needed for a wall project. Input wall dimensions, block size, and mortar gap to get accurate estimates including blocks, mortar, and waste.
Published by:
isCalculator Editorial Team
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How to use this tool?
Concrete Block Calculator – Quick Guide
This calculator estimates the number of concrete blocks needed for a wall, including mortar and waste. All measurements are in imperial units (feet and inches).
- Enter Wall Dimensions – Input the wall length and height in feet (e.g., 20 ft x 10 ft).
- Set Block Size – Default block is 16 in x 8 in. Adjust if needed.
- Mortar Gap – Default is 0.5 inches. Change for thicker/thinner joints.
- Waste Percentage – Default 5% accounts for breakage and cuts.
- Price per Block (optional) – Enter cost to see total material cost.
- Click “Calculate” – Results show:
- Number of blocks needed (rounded up).
- Estimated mortar volume (cubic feet).
- Total cost if price was entered.
Tip: All dimension fields must be positive numbers. Zero is not allowed for lengths or heights.
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Frequently Asked Questions
Measure the length and height of the wall in feet. For irregular walls, break into rectangles and sum areas.
Common nominal size is 16 inches long by 8 inches high, but actual size is slightly smaller to allow for mortar joints.
A typical estimate is 0.3 cubic feet of mortar per 100 blocks, but it varies with joint thickness and block type.