Concrete Block Calculator | Estimate Blocks, Mortar & Cost

Types of Concrete Blocks

Concrete blocks generally fall into two categories:

• Solid Blocks: Often used for retaining walls and structural support.
• CMUs (Concrete Masonry Units): Hollow blocks, also called cinder blocks, that require filling with concrete during installation. The most common size is 8" x 8" x 16".

A standard concrete block wall usually requires 1 1/8 blocks per square foot of wall area.

Step-by-Step Concrete Block Calculator: Estimate Blocks, Mortar, and Cost

1. Wall Dimensions: Enter the width and height of the wall in units such as feet, inches, meters, etc.
2. Block Size: Select from standard sizes like 8x8, 12x8, or 16x8 inches.
3. Block Price (Optional): Enter the price per block for cost estimation.

Formula for Wall Area:

Formula for Block Count:

Add an extra 5%-10% to account for cutting and breakage.

Mortar and Sand Estimation:

Mortar is essential for bonding blocks together. If you’re mixing your own mortar, a 1:3 cement-to-sand ratio is typical. You’ll need about three bags of cement for every 100 blocks and one cubic yard of sand per seven cement bags. To ensure you account for the total weight of materials, use our Concrete Weight Calculator for precise estimates.

For pre-mixed mortar, refer to the product specifications for coverage details.

• Mortar Bags:

• Sand Amount (cubic yards):

Cost Estimation:

For projects like driveways or pathways, pair this calculator with our Curb and Gutter Calculator to estimate materials and costs for combined structures.

Example Calculation

Input Details:

• Wall Width: 20 ft

• Wall Height: 10 ft

• Block Size: 16x8

• Block Price: $1.5

Step-by-Step Calculation:

1. Convert Wall Dimensions to Feet:

Wall Area:

2. Block Area:

For a 16x8 block:

3. Number of Blocks:

4. Mortar Bags:

5. Sand Amount:

6. Cost Estimation:

• Blocks:

• Mortar:

• Sand:

Tools for Building a Concrete Block Wall

Ensure you have these essential tools for your project:

• Brick Trowel: Spread mortar evenly.

• Mason Line: Keep blocks level and straight.

• Level: Verify block alignment.

• Jointer: Smooth mortar joints.

• Tape Measure: Measure dimensions accurately.

• Mixing Tub: Prepare mortar without dirtying your wheelbarrow.

For outdoor projects requiring electrical work, always check wire safety with our Voltage Drop Calculator.

Standard Concrete Block Sizes

Common concrete block sizes include:

• 8” x 8” x 16”: Most widely used, covering 0.89 sq. ft. per block.

• Additional sizes range from 4” to 14” in thickness for various structural needs.

Refer to the table below for nominal and actual dimensions:

Use our Concrete Block Calculator to get precise estimates and ensure you have the right materials for the job. For additional assistance, consider consulting with a masonry expert.