Counting blocks by wall area
A standard 8×8×16 CMU shows 8 inches of height and 16 inches of face per block, so each block covers about 0.89 square feet of wall — the industry rounds to <strong>1.125 blocks per square foot</strong>. Multiply wall area by that, add 5–10% for breakage and the blocks you'll cut around corners and openings.
Mortar goes with the count
Plan on roughly <strong>3 bags of mortar per 100 blocks</strong>, plus one cap block per linear foot if the wall gets capped. Cores that will be filled with rebar and concrete change the concrete order, not the block order — count blocks first, then run the fill calculator for the poured cores.