Answer:
According to my search, the answer is this.
Black holes come in several different sizes which are defined by their mass. Small black holes are usually the result of a relatively short and violent collapse of a star.
Step-by-step explanation:
It only has mass. The amount of matter that has fallen into the black hole determines its mass. The more mass/matter a singularity has the larger its event horizon. So, the greater the black hole's mass the larger it is.