The Superhero Database Classification number, or SHDB Class, is a number that represents the overall 'power' of a character. All traits of a character are used for calculating the Classification.
What it DOESN'T mean
This doesn't mean that a higher class would always beat a lower class character. But the bigger the difference in Class is, the more obvious it is who'll win in a fight.
How is this calculated
( INT^1.3 + (STR*0.5 )^2 + (SPE*0.5)^2 + DUR^1.6 + (POW + (SPS*SPL))^2 + COM^1.8 ) ^ TIER
Super Power Score and Level
Every Super Power has a score (SPS) that is used to calculate the Class. Each Super Power also has 3 levels (SPL). The level is set when connecting that Super Power to a character. The level determines the final score, of the Super Power, being used in the calculation.
Who wins?
Here is the thin with Gohan, he was stated in his Ultimate/Mystic form to be more powerful than Super Saiyan 3 in this form and he doesn't put any strain on his body in this form either. I think Gohan could win this fight. I'm interested in what everyone else thinks. Especially because Janemba's so called "weakness" is being insulted so lol. Not that Gohan knows that of course but I go with Gohan here.