Concrete Block Calculator

Calculate the number of concrete blocks and amount of mortar needed for your wall project.

Wall Dimensions

Unit System

Wall Length (ft)

Wall Height (ft)

Block Size (Nominal)

Mortar Joint thickness (in)

Waste Factor (%)

Material Estimate

Enter dimensions to estimate materials

Overview

CMU (Concrete Masonry Unit) walls are a staple of durable construction. This calculator estimates the total number of blocks based on the surface area of your wall, accounting for the vertical and horizontal mortar joints that separate each block.

💡

Pro Tips

Always order at least 5-10% extra blocks to account for breakage during transport or cutting at corners.
A standard 3/8" (9.5mm) mortar joint is the industry default for most masonry work.
Stagger your blocks in a 'running bond' pattern for maximum structural integrity.

Fun Facts

"Standard hollow concrete blocks are also known as breeze blocks in the UK or CMUs in the US."
"The actual size of a block is typically 3/8" smaller than its nominal size to account for the mortar joint."
"Concrete blocks are exceptionally fire-resistant and provide excellent soundproofing."

Formula: Number of Blocks = (Wall Area) / (Block Length × Block Height)

Used with this

Similar tools that might be useful

AC Room Size Calculator

Find the perfect AC unit size based on room dimensions and environmental factors.

AC Tonnage Calculator

Calculate air conditioning capacity in tons and BTU for your home with precision.

Air Changes per Hour (ACH)

Measure ventilation effectiveness by calculating room air replacement rates.