How this calculator works
A standard 8×16 inch concrete block covers about 0.89 sq ft of wall with mortar, so it takes roughly 1.125 blocks per square foot. The calculator applies that rate and adds 5% for waste.
Worked example — a 20 ft × 8 ft wall:
160 sq ft × 1.125 × 1.05 = 189 blocks.
160 sq ft × 1.125 × 1.05 = 189 blocks.
Blocks per square foot
The 1.125 figure assumes the common 8×8×16 inch block. Half-height or specialty blocks will change the count.
Frequently asked questions
How many concrete blocks per square foot?
About 1.125 blocks per square foot for standard 8×16 inch units with mortar joints.
How many blocks for a 20×8 wall?
Roughly 189 blocks including a 5% waste allowance.