The average cinder block, which measures 8 inches wide by 8 inches tall by 16 inches long, weighs approximately 36 to 40 pounds. Factors such as block shape — which can include solid, semisolid, stretcher and open cell — and block material determine the actual weight.
A standard 12-inch cinder block measuring 12 inches by 8 inches by 16 inches weighs approximately 45 to 60 pounds. A standard 16-inch block, which measures 16 inches by 8 inches by 16 inches, typically weighs 45 to 70 pounds. High-density blocks are usually made with a combination of cement and aggregates such as gravel or sand. Low-density blocks, which are used in partitions and non-load-bearing walls, replace sand and gravel with clay, shale, slate, pumice or scoria.