The smallest cell in the human body is the sperm cell. It’s a reproductive cell, much smaller than most other human cells. Sperm cells are only about 4 micrometers long, which is about 20 times smaller than a grain of sand!

The largest cell in the human body is the female egg cell, also known as the ovum. Unlike sperm cells, ova don’t move around. They are much bigger to store nutrients needed for early embryonic development. An ovum is about 0.1 millimeters in diameter, which is roughly the width of a human hair.