Concrete Block Fill Calculator

This Concrete Block Fill Calculator helps you estimate the amount of concrete or grout needed to fill the cores of concrete masonry units (CMUs). Use either wall dimensions or block count to calculate fill volume in both metric and imperial units.

Advanced Options
5%
cu ft
Nominal Length Nominal Height Shell Web

Fill Calculation Results

0.00 m³
0.00 yd³
0.00
Cubic Feet
0
80 lb Bags
0
Blocks Used
$0.00
Estimated Cost

How We Calculated This

Step 1: Determine Number of Blocks
Number of Blocks = (Wall Length × Wall Height) / (Block Length × Block Height)
Calculating…
Step 2: Calculate Core Volume per Block
Core Volume = (Block Length – Total Web Thickness) × (Block Width – 2 × Shell Thickness) × Block Height
Calculating…
Step 3: Calculate Total Fill Volume
Total Fill Volume = Core Volume × Number of Blocks
Calculating…
Step 4: Apply Wastage
Volume with Wastage = Total Fill Volume × (1 + Wastage Percentage / 100)
Calculating…
How the Concrete Block Fill Calculator Works

The Concrete Block Fill Calculator estimates the volume of concrete or grout needed to fill the hollow cores of concrete masonry units (CMUs).

Concrete blocks typically have hollow cores that can be filled with concrete or grout to increase strength, add insulation, or provide a solid base for attachments. The calculator accounts for the actual fillable space within each block, excluding the material used for the block’s shell and internal webs.

You can calculate based on either wall dimensions (length, height, and thickness) or by directly entering the number of blocks. The calculator supports both imperial and metric units and provides conversions between them.

Frequently Asked Questions
What is the difference between nominal and actual block dimensions?

Nominal dimensions include the mortar joint, while actual dimensions are the physical size of the block. For example, an 8×16 inch nominal block typically has actual dimensions of 7.625×15.625 inches.

How accurate is this Concrete Block Fill Calculator?

This calculator provides a close estimate for planning purposes. Actual requirements may vary based on block design, workmanship, and site conditions. Always add a wastage factor (5-10% is typical).

Can I use this calculator for different block sizes?

Yes, the calculator supports standard block sizes (6″, 8″, 10″, 12″) and custom sizes. You can input any block dimensions in either imperial or metric units.

What is shell thickness and web thickness?

Shell thickness refers to the thickness of the outer walls of the concrete block. Web thickness refers to the thickness of the internal dividers (webs) within the block that create the hollow cores.

Quick Reference: Fill Volume per 100 Blocks

Wall Thickness Cubic Yards Cubic Meters Cubic Feet
6 inch 0.75 0.57 20.25
8 inch 1.00 0.76 27.00
10 inch 1.25 0.96 33.75
12 inch 1.50 1.15 40.50