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Masonry Core Fill & Grout Calculator
Updated Aug 25, 2026 Reviewed Aug 25, 2026
Estimate CMU core and bond-beam grout volume, bag yield, rebar displacement and cost for multiple walls.
CMU grout material takeoff
Enter walls, approved grout pattern and verified block void volume
Result
Calculation summary
Enter values to see the result
Your result, breakdown, assumptions, and warnings will appear here.
Wall preview
Vertical cells and bond-beam course
Estimated blocks
180
Order volume
0.44 m³
Whole bags
32
How to use this calculator
- 1Add each wall and enter its dimensions.
- 2Enter block face size, cores per block and manufacturer void volume.
- 3Choose all, every-nth or specified vertical cells and bond-beam courses.
- 4Enter bag yield, waste, optional rebar displacement and price.
Formula
Grout volume = filled core-block count × grout volume per core per block
Vertical cells and additional bond-beam cells are counted without double counting, then entered rebar displacement is deducted.
Calculation steps
- Round wall dimensions to whole block courses and lengths.
- Count available and selected vertical cell columns.
- Add bond-beam cells not already included.
- Subtract entered cylindrical rebar displacement.
- Apply waste and round to whole bags.
Worked example
A wall ten blocks long and six courses high contains 60 blocks; grout volume depends on selected cells and entered void volume.
Assumptions
- Block layout is an orthogonal wall estimate without corner interlock adjustments.
- Void volume per core per block is entered from selected unit data.
- Bond-beam courses fill all cells on those courses.
- Rebar is represented as straight cylinders.
- Structural grout locations and reinforcement are supplied by an approved design.
Sources
Frequently asked questions
Does it decide which cells need grout?
No. Choose the pattern required by approved project documents.
Why enter void volume?
Actual block core geometry varies by manufacturer and configuration.
How are bond beams handled?
Selected courses add cells not already included in vertical grouted columns.
Is rebar displacement required?
No. Enter zero bars to omit it.
Does this calculate grout strength or mix design?
No. It is a material takeoff only.
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