🪣 Concrete Block Fill Calculator
Calculate how much grout fill you need for the hollow cores of a concrete block wall.
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blocks
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cu ft
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%
What this calculator does
This tool calculates how much grout or concrete fill is needed to fill the hollow cores of a concrete block wall, whether filling every core or a percentage for partial reinforcement.
The formula
Total fill volume = number of blocks × core volume per block × the percentage of cores being filled. A standard 8 in × 8 in × 16 in block has roughly 0.45 to 0.55 cubic feet of core volume, though this varies by manufacturer.
Bag estimates assume an 80 lb bag yields about 0.6 cubic feet of grout, a common industry rule of thumb — check your specific product’s yield for accuracy.
Last reviewed August 2026