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Estimate mortar for block and brick walls. Enter wall area and joint thickness for mortar volume in cubic feet, premix bags, and site-mix batch counts.
Estimate retaining wall blocks, base gravel, and drainage for landscape walls. Enter wall length and height for block count and backfill materials.
Free concrete calculator for slabs, footings, and pours. Enter length, width, depth to get cubic yards, cubic feet, and bag counts with waste factor.
Convert wall length and height from feet to square inches to match standard block face dimensions stated in inches.
Wall Area (sq in) = Length (ft) × Height (ft) × 144Divide total wall area by the nominal face area of one block. Standard 8×8×16 block has an 8×8 in face (128 sq in) — the 16″ length runs into the wall.
Blocks = Wall Area (sq in) ÷ Block Face Area (sq in)Add 5% for broken blocks, corner cuts, and partial units at openings. Increase to 10% for complex layouts with many windows and doors.
Order = ceil(Net Blocks × 1.05)Updated: July 2026
A 40 ft long × 8 ft high CMU wall (320 sq ft) using standard 8×8×16 blocks requires about 360 blocks net, order 378 with 5% waste.
A single 16×8 ft dividing wall needs roughly 144 blocks. Confirm door and window openings reduce count before final order.
A short 12×2 ft landscape wall uses about 27 blocks — a partial pallet. Combine with another project or buy by the piece at big-box stores.
Determine how many concrete masonry units (CMU blocks) to order for a wall, foundation, or partition before delivery. Enter wall dimensions and block face size to get net block count plus a 5% waste allowance for cuts and breakage.