CMU Block Count Calculator

Calculate the number of concrete masonry unit (CMU) blocks needed for a wall. Supports standard 8x8x16 and other common block sizes.

Results

Visualization

How It Works

Standard CMU blocks are nominally 8x8x16 inches, but actually 7-5/8 x 7-5/8 x 15-5/8 to allow for 3/8 inch mortar joints. One standard block covers 0.889 sq ft of wall area. A standard block wall uses about 1.125 blocks per square foot. Mortar joints should be 3/8 inch thick. An 80-lb bag of Type S mortar lays approximately 30 standard blocks. Always start from corners and work inward, checking level every 2-3 courses.