CMU Calculator: Wall Grout / Cell Fill Volume & Bags

Estimate grout (cell fill) for CMU walls using industry tables. Enter wall length & height, choose wall thickness and vertical bar spacing (e.g., “all cells”, 16″/24″/32″ o.c.). Subtract openings and add a waste allowance. Results show grout volume in yd³, ft³ and m³ plus editable bag counts (80-lb fine/coarse). Notes, formulas, and FAQs included.

Units Metric (m, mm) US Customary (ft, in)

Wall length

Wall height

Wall thickness

Grout pattern / vertical spacing

Coefficients from contractor tables (per 100 ft² of wall) by thickness and spacing.

Waste allowance

Covers spillage and variation (many jobs use 3–7%).

Subtract openings (optional)

Enter up to 5 rectangular openings to subtract from wall area (clear width × height).

#	Width m	Height m
1
2
3
4
5

This subtracts only the opening area; it does not re-space bars through openings.

Per-bag yields (editable)

80-lb Core-Fill Grout — fine (default)

ft³ / bag

QUIKRETE Core-Fill Grout Fine ~0.68 ft³/80-lb bag.

80-lb Core-Fill Grout — coarse

ft³ / bag

QUIKRETE Core-Fill Grout Coarse ~0.65 ft³/80-lb bag.

Results

Wall area (net)

0.000 m²

0.0 ft²

Openings subtracted from gross area.

Grout volume

Net: 0.000 yd³

With waste: 0.000 yd³

0.0 ft³ • 0.000 m³

Bag counts (from total with waste)

80-lb Fine (~0.68 ft³): 0

80-lb Coarse (~0.65 ft³): 0

Assumed coefficient

Using — (yd³ per 100 ft²) for a — wall at —.

How to use this CMU grout calculator

Select metric or US units.
Enter wall length and height.
Choose wall thickness and grout pattern (all cells or vertical spacing).
Optional: enter openings to subtract their area.
Set waste percentage. Review grout volume and bag counts (edit yields to match your product sheet). Round up for ordering.

Method, formulas & assumptions

Area-based method: Use tabulated grout requirements in yd³ per 100 ft² by wall thickness and vertical bar spacing. Net volume V = A_net,ft² × (Coef/100), then apply waste: V_w = V × (1 + waste%).
Openings: Subtract clear opening area from wall area. This does not re-space bars through the opening; adjust manually if required by the engineer.
Bag counts: bags = ⌈ V_w,ft³ / yield_{per bag} ⌉. Defaults reflect common 80-lb core-fill grout yields.
Scope: Planning estimate. Does not enforce pour height, consolidation, or rebar details; see project drawings and local code (ASTM C476 grout; typical slump 8–11 in).

References

Grout requirements per wall thickness & spacing (yd³ per 100 ft² and per 100 blocks). Fairbanks Materials grout table.
Per-bag yields: QUIKRETE® Core-Fill Grout Fine (80-lb) ~0.68 ft³; Coarse (80-lb) ~0.65 ft³. Fine data sheet • Coarse data sheet.
Alternate product yields (blocks/cores per 80-lb bag): SPEC MIX® Core Fill Grout. Tech sheet.

FAQs

Should I use “per 100 ft²” or “per 100 blocks”?

This tool uses the per 100 ft² coefficients so openings are handled cleanly via area. If you need block-based estimating, use the per-100-block values from the same table and your block count.

What slump and code requirements apply?

Most preblended core-fill grouts are designed to meet ASTM C476 at a flowable 8–11 in slump. Follow the product data sheet and building code limits for pour height, consolidation, and lift intervals.

How do I account for bond beams and lintels?

Bond beams and lintels usually add grout. If not already included in your wall area, add their length × width × depth as additional volume.