Planck length

very small-scale unit of length

The Planck length (P) is a very small unit of length. It is calculated from three physical constants: the speed of light, the Planck constant, and the gravitational constant.

It is about 1.616255×10−35 m or about 10−20 times the size of a proton. It is one of the Planck units, defined by Max Planck. It is an important length for quantum gravity because it may be the size of the smallest black holes.[1]

Related pagesEdit


  1. Baez, John. "The Planck Length".