“Honestly, the many feats of endurance possible are truly mind blowing. Take Calanor for instance. He fell off a cliff over a couple hundred feet high, took three disintegrate spells directly, got mauled by a manticore while fending off a wyvern, got turned into a porcupine by a needle trap, drank a vial of acid as part of a dare, and still had enough fight to go running into the fray of a battle between the town guard and a large group of particularly bandits, and only stopped to drink one or two healing potions during this entire ordeal. It’s ridiculous! And everybody wonders why I don’t worry about collateral damage with him.”Visna, reminiscing about her last adventure
HP! Arguably the most important thing since games first integrated combat, this valuable resource determines how close a creature is to death, and can be depicted in many ways from injuries, to luck, or tenacity.
But as with all information, it’s not very useful with some way to determine it. Enter, Hit Dice! Of course I did an article about that topic, so I won’t cover the details of that, but they do play a vital role in calculating HP, by determining how many hit points a creature has each level.
For the first level, you always use the largest number on your hit die instead of rolling or taking a standard number. This prevents issues with only having 1 hit point at level 1, which is really bad since you would fall unconscious if you took any damage, or die instantly if you took 2 points at once. And that’s not fun.
Beyond the first level, a creature can choose to either roll the die and add the result to your hit points (most groups re-roll 1s), or take an average roll which is always detailed on the class for which you got each set of hit dice, and is always regular. Monster stat blocks actually use set numbers for the displayed hit points, though you can also roll hit points for them if you really want a unique value for them. These set numbers are also found on page 276 of the DMG for your convenience.
For all levels, creatures add their constitution modifier, and any other bonuses (such as the Hill Dwarf’s Dwarven Toughness feature, or the Tough feat). Beyond that, you’re pretty much set. There is magic (such as Aid) that does increase maximum health, but the math is usually pretty simple.
Simple and essential, HP is incredibly useful, and is to be cherished. I hope that anyone reading this finds something of use for the next time they determine HP for a monster or PC. Good luck, and have fun! Now don’t mind me as I proceed to leap off a mountain for a cool superhero landing.