How the calculation works
Fill volume = units being filled × manufacturer core volume per unit. Add the selected fill allowance once.
A worked example
100 units at an illustrative 0.25 ft³ per unit need 25 ft³ before allowance, or 0.9259 yd³.
What to check before using the result
- Purchased spare blocks do not automatically increase the wall’s fill volume.
- Use a fill material and yield specified for the project; ordinary concrete is not interchangeable with every masonry grout.
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References & product information
Method prepared 2026-10-21. See our calculation and editorial methods. Spotted a problem? Tell us about it.