Comment by burnt-resistor

A black hole is really just a singularity with infinite density by definition, but finite mass.

The size and density of the Schwarzschild volume is determined only by mass (stationary, non-rotating). It's proportional to the inverse square of mass. Density = 3c⁶/32πG³M².

SMBHs have densities ~0.5 kg/m³ between thin air and water.

Stellar BHs are ~1e19 kg/m³ several orders of magnitude more than a neutron star.