Block Calculator
Calculate the number of concrete blocks needed for a wall, including mortar allowance and waste factor.
Published by:
isCalculator Editorial Team
Was this calculator helpful?
How to use this tool?
How to Use the Block Calculator
This calculator estimates the number of concrete blocks needed for a wall. All inputs are in imperial units (feet and inches).
- Enter Wall Dimensions – Provide the wall's length and height in feet.
- Set Block Size – Adjust block length and height in inches (defaults: 16" x 8").
- Specify Mortar Joint – Enter the mortar thickness in inches (default: 0.375").
- Add Waste Percentage – Include extra blocks for cuts and breakage (default: 5%).
- Click "Calculate Blocks" – The result shows the total number of blocks needed, including waste.
Tip: Ensure all values are positive numbers (mortar and waste can be zero). The calculator automatically accounts for mortar joints in block area calculations.
Previous Results
| Result | Inputs | Date |
|---|
Frequently Asked Questions
Measure the length and height of the wall in feet. For irregular shapes, break the wall into rectangles and sum the areas.
Common concrete block sizes are 16 inches long by 8 inches high, but you can enter custom dimensions.
Waste accounts for cuts, breakage, and mistakes. A typical waste factor is 5-10%.