How small are the strings proposed by string theory?

In string theory, strings are proposed to be incredibly small, with a characteristic length of approximately ${10}^{-33}$ cm.12

This dimension is known as the Planck length, which is derived from a combination of fundamental constants: Planck’s constant, the speed of light, and the gravitational constant. Because of this infinitesimal size, strings appear as points to our current observational capabilities, even though they possess linear extension. This scale is far smaller than the distances that can be probed by particle accelerators on Earth, which is why they have not been directly detected.21