Weak monsters (CR 0 to 1) scale differently, making it difficult to make Sergeant Orcs or Gnolls on the fly. If you added 30 hit points to a creature that is CR 2, it would move up to CR 3. So if you added 30 hit points to a CR 0.5 creature, it would now have a CR of 1, not 1.5. In this context, leveling up a monster refers to bringing it up to the next CR level. If you wanted to get really nitty-gritty, you could swap out +1 attack, 7 hp, et cetera for quarters of the next CR level. This isn’t exact due to scaling proficiency and AC, but should provide an easy rule of thumb that makes it easy to swap in “leader” monsters. Attack damage by 5 (or any fraction thereof).Hit points by 15 (or any fraction thereof).

If you increase any of the following statistics by the amount mentioned, the creature gains half of the next CR level. I did a quick analysis of the monster creation section, and this is what I found. I vaguely remember that this was something somewhere in 4e, and I was wondering if we could do something like that for 5e. I like the idea of the template system where a DM can quickly change a monster’s level to suit the needs of the upcoming combat.

Dnd 5e monster template