DISCLAIMER! THIS IS NOT OFFICIAL, BUT YOU ARE ALLOWED TO USE THE MEASUREMENT FREELY.
Universe Classification is a method of determinating the size of a valid 'Verse'
The Universe class is the basic size of a universe that contains galaxies, verses stretching from 80 Billion LY to ~500 Billion LY are considered Universes. Most are determined on size.
F - Class Universe
An F-class universe is not yet a universe but is considered one since it contains multiple galaxies. They are below 90 Billion LY
E - Class Universe
An E-Class Universe is the smallest valid type of Universe, which is under 90 Billion LY in diameter
D - Class Universe
A D-Class Universe is a small-medium sized universe, usually over 90 Billion LY and under 150 Billion LY
C - Class Universe
A C-Class universe is a medium-sized Universe, usually between 150 Billion LY and 210 Billion LY
B - Class Universe
A B-Class Universe is a medium-large Universe, between the size of 210 Billion LY and 350 Billion LY
A - Class Universe
An A-Class universe is a Large universe between the size of 350 Billion LY to 500 Billion LY
S - Class Universe
An S-Class universe is a universe beyond 500 Billion LY but is not yet a multiverse. These are rare.