User blog comment:ArceusBowser44/First Calc--Black Hole Ability/@comment-33067344-20180911142710

The radius part is on meters; not cm.

(299792458² * 0.288) / (2 * 6.67408e-11) = 1.93915485e26 kg.

We can calculate the energy of the created star, so.

U = (6.67408e-11)*(1.93915485e26^2)/(5*0.288) = 1.74282547e42 joules, which is 416.54 tenatons of TNT. Large Star level.