10-50meters Fighters
51-200meters Corvettes
201-499meters Frigates
500-1000meters Destroyers
1001-2000meters Cruisers
2001-5000meters Carriers
5001-10000meters Battleships
10001-20000meters Capital Ships
20001+meters are Titan Ships
Now even though these are the classification their are sub categories depending on what configuration the ship is an example would be a ship that has most of its hull covered with weapons theses ships will have heavy in the name but these ships trade movement for firepower. Fighters also have Bombers which are just fighters equipped with explosive ordnance. This is just to give an idea of what ships are what hope this helps and when I start having space battles people will not be confused about what ships what it allows for easier picturing of the scenes I describe.