Large Project Estimate

Cinder Blocks for
20x20 Wall

Get an accurate material count for a 400 square foot concrete block wall.

Wall Dimensions (Feet)

Block Specifications

Estimation Results

Enter dimensions to see results

Pro Tip

A standard 8x8x16 block actually measures 7 5/8" x 7 5/8" x 15 5/8" to account for 3/8" mortar joints.

How Many Blocks for a 20' x 20' Wall?

A 20x20 wall is a significant project covering 400 square feet. For a wall this size, you will need approximately 450 to 500 blocks.

Material Requirements

  • Total Square Footage: 400 sq ft.
  • Block Count (Net): 450 blocks.
  • With 10% Waste: 495 blocks.
  • Mortar Needed: ~35 to 40 bags of pre-mix (80lb).

Contractor Tip

"For a 20x20 wall, you are looking at roughly 4-5 full pallets of blocks. At this volume, most masonry yards will offer a discounted commercial rate and job-site delivery."