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.
Surtur has enough power to burn Yggdrasil and all realities.
Yggdrasil contains a maybe-infinite amount universes that are complex and fully-formed. And all realities have their own Yggdrasil.
Surtur has the power of thousand suns, and can destroy an entire galaxy.
Surtur has been known to give Odin a run for his money
From a mere sword-clash with Odin, they were able to shake The Nine Realms (which I mentioned earlier are universes).
Surtur was able to forge copies of Mjolnir—the hammer that contains a galaxy-sized superstorm that destroyed several planets, suns and moons.