How this calc works

A standard CMU lays up 8 inches high by 16 inches long including the mortar joint — so one block faces 8/9 of a square foot, and a wall takes about 1.125 blocks per square foot of face area. This calc runs your wall area against that block coverage and returns the block count.

Block math is forgiving in one way and unforgiving in another: the coursing is regular, so the count is predictable, but openings, bond beams, and control joints all change the order. Get the field count here, then layer in the bond-beam and grout-cell calcs for a reinforced wall.

Common mistakes

The mistake is counting the field and forgetting the special units — bond-beam blocks, half blocks at openings, and corner units are separate from the standard count and easy to under-order.

The second is ignoring grout and mortar. The block count is one line; mortar bags, grout for filled cells, and rebar are their own calcs and their own cost — see the related masonry pages.

RELATED FORMULAS