The smallest measurement of length is known as the Planck length. It is approximately 1.616255 × 10-35 meters. This measurement is derived from fundamental physical constants and represents the scale at which classical ideas about gravity and space-time cease to be valid, and quantum effects dominate.
The Planck length is named after Max Planck, the physicist who first proposed it. It is considered the smallest meaningful length in the universe, beyond which the concept of distance becomes meaningless according to our current understanding of physics.