CMU Block Calculator

Enter your wall dimensions and block size to estimate how many concrete masonry units (CMU) you need, plus mortar bags and a cost comparison across block sizes.

Wall Length (ft)

Wall Height (ft)

Mortar Joint (in)

Doors (deduct ~20 sq ft each)

Windows (deduct ~15 sq ft each)

Waste Factor (%)

Pricing (edit to match local rates)

8"x8"x16" Block ($)

8"x4"x16" Block ($)

12"x8"x16" Block ($)

Wall Elevation

Hover for details • elevation view

Net Wall Area

160 sq ft

Gross 160 sq ft minus openings

8x8x16 Blocks Needed

189

Incl. 5% waste

Mortar (80 lb bags)

7 bags

For 8x8x16 blocks

Purchase Option	Quantity	Est. Cost
8x8x16 BlockBest value	189 blocks + 7 mortar bags	$425.25
8x4x16 Block	378 blocks + 14 mortar bags	$661.50
12x8x16 Block	189 blocks + 9 mortar bags	$661.50

Best value: 8x8x16 Block at $425.25The 8x8x16 block is the cheapest option for this wall at current prices. Standard 8x8x16 blocks are the most common choice for structural walls. Half-high 8x4x16 blocks take more units but weigh less per block, making them easier to handle. The 12" wide block provides extra insulation and structural capacity for below-grade or load-bearing walls.

This is a material estimate only. Actual block counts may vary based on bond pattern, corner details, lintels, and structural requirements. Always consult a mason or structural engineer for load-bearing walls.