The mass of the smallest-possible black hole is called the Planck Mass (~21 micrograms). Such a black hole would have a Schwarzschild radius of 1 planck length,

The mass of the smallest-possible black hole is called the Planck Mass (~21 micrograms). Such a black hole would have a Schwarzschild radius of 1 planck length, and would evaporate in 1 planck time. The planck mass is also considered to be the largest-possible mass of an elementary particle. https://en.wikipedia.org/wiki/Planck_mass https://en.wikipedia.org/wiki/Planck_mass