How big are blackholes?

They can be only a few miles across, while others are several million miles across.

A black hole can have a mass of about 50 billion suns, which is the limit.

Black holes can grow larger, depending what it sucks.

Since black holes are suns that have exploded, explosions spread, causing the black hole to emerge.

When our sun goes to the next stage in life, the black hole, it might not make a black hole, or a very small one.