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.
1) Iron Man got wrecked by Thor in A1, who in turn was wrecked by Hulk.
2) Iron Man got wrecked when fighting Hulk in Hulkbuster, an armor literally made to fight Hulk
3) Iron Man does okay against Loki and Cap, while Hulk obliterates Loki who in turn does the same to Cap.
4) Can't beat Ultron, who gets one-shotted by Hulk, and who suffers the Loki treatment at the hands of Hulk.
5) Uses tricks and still only kills one or two leviathans, while Hulk uses brute force and destroys half a dozen of them.
6) I could keep going but do I have to?