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.
So, from Chapter 200ish we know their comparison, and in a separate calc, I found that Kid Goku is 88.6482939633 cm tall.
Kid Goku height = 221 pixels or 88.6482939633 cm
Every pixel = 0.40112350209638 cm
Boulder height = 1151 pixels or 461.6931509129 cm
Boulder length = 1013 pixels or 406.3381076236 cm
Boulder width = 784 pixels or 314.4808256436 cm
Boulder Volume = 58997710.254687764 cm3
Boulder Density = 3.0 g/cm3
Boulder Weight = 176993130.7640633 grams or 195.10152999714623 tons (Class K)