How it works
Divide the wall face area by the face of one block. A standard cinder block face is 16 in × 8 in.
Blocks = (Wall length × height in inches) ÷ (Block length × height in inches)
Example
A 10 ft long, 8 ft high wall with 16 × 8 in cinder blocks needs 90 blocks — add ~10% for cuts and breakage.