Originally written and posted on Medium.com February 26th, 2019

“What is a Spell Slot? Spells have levels, right? Are they the same as Spell Slot levels? How many spells do I know? Do I have to prepare spells? What the actual f**k is going on?”

Author Note: Oh man, this article is nearly two years old and still being found! As of 19/01/2020 I’ve made some minor amends — mostly typos, some minor rule corrections (the irony of this article having rules errors in it is not lost on me, but does highlight the need for itself) and addressing some reader comments. Thanks to all for reading and sharing. You can find more of my work on my Itch.io page, or follow me on Twitter.

If there is one thing that crops up all the time with new people learning D&D, it’s that the rules around spell casting are just super hard to “get”.

It’s great that different classes that cast magic do so in different ways, as it allows for an awesome variety in both flavour and mechanics. But hot damn the PHB’s rules for magic are spread just a touch all over the place, and so I seem to spend my entire life explaining the rules of magic to new players.

Let’s explain it once and for all. Step by step, with examples.

I’m gonna start with the rules that apply to all classes, and get more specific from there. So, Spell Slots. Let’s do this.

“I roll to make a tiny water ball”

“First and foremost; the fk is a Spell Slot?”**

A Spell Slot is D&D 5E’s mechanism through which a spell is cast. Think of a given Spell Slot as being like a barrel of a revolver — every time you cast a spell, you “use up” a Spell Slot, and you (usually) get all your Spell Slots back every time you take a Long Rest. Each class gets a number of Spells Slots to use per day.

Both spells and Spell Slots have levels. This is going to be a major point of confusion, so read on carefully! When it comes time to cast a spell, you use up a Spell Slot that is the same level as the spell or higher.

For example: your character has two 1st level Spell Slots, and one 2nd level Spell Slot. You want to cast Burning Hands, a 1st level Spell. You can expend (“use up”) one of those 1st level Spell Slots OR your 2nd level Spell Slot in order to cast Burning Hands through that slot. Easy!

“Why would I want to use my 2nd level Spell Slot in order to cast a 1st level spell? Surely I should save that to cast a 2nd level spell?” — you, totally justifiably.

You’re absolutely right! However, there are a couple of reasons you might want to use a Spell Slot of a higher level than the spell itself.

• maybe you’ve used up all your Spell Slots of the same level for the day, but you still really wanna cast that spell.
• some spells become more powerful when used in a Spell Slot higher than their own level. Think of it as like “charging up” a spell by “firing it through” a higher level slot.

Every class has a number of Spell Slots per day based on their level. For example, a 4th level Druid has four 1st level Spell Slots, and two 2nd level Spell Slots. The more Spell Slots, the more spells you can cast before needing to rest and recover your expended Spell Slots.

Finally, finally, one last thing to note — characters also have levels. I know you know this. But, and say it out loud with me; “my character level is NOT my spell level or Spell Slot level”. The designers of D&D have a serious problem when it comes to the word “level”, so I wanted to clear that up before we go on.