Planetary-mass black holes... expand?

[JMBuilder]

I was under the impression that a black hole about 12 times the mass of the Earth would be only a few meters in size at most, yet when I edit the mass of a black hole to that point, it expands to several kilometers.

Is this a bug, or would planetary-mass black holes actually have larger event horizons?

[tkulogo]

A 12 earth mass black hole should be more like 4 inches in diameter. If it's showing up as kilometers wide, it's a bug.