Where is the explicit rule that states a wizard must have an appropriate spell slot to prepare a spell?

Asked another way: Can a wizard prepare a spell he does not have a spell slot for?

I am having trouble finding the explicit rule that states a wizard must have the appropriate spell slot available to prepare a spell he knows.

I am aware that preparing a spell one cannot cast is potentially a pointless exercise, but it does have some potential implications when it comes to item creation. Before going down that rabbit hole - I could use some help finding the exact rule or rules governing this mechanic.

To learn, prepare, or cast a spell, the wizard must have an Intelligence score equal to at least 10 + the spell level. The Difficulty Class for a saving throw against a wizard’s spell is 10 + the spell level + the wizard’s Intelligence modifier.

This clearly states that learning (knowing), preparing, and casting spells are three separate mechanics. And does not state the wizard must have an appropriate spell level slot in order to add it to their spell book - and thus know the spell.

You can cast a spell at a lower caster level than normal, but the caster level you choose must be high enough for you to cast the spell in question, and all level-dependent features must be based on the same caster level.

This mechanic ties casting the spell to a minimum caster level. But does not explicitly state or exclude preparing the spell at an even lower caster level - just that you wouldn't be able to cast it. Leading one to believe it could be possible to prepare a spell (but not cast it) if one does not have enough caster levels.

Spell Slots The various character class tables show how many spells of each level a character can cast per day. These openings for daily spells are called spell slots. A spellcaster always has the option to fill a higher-level spell slot with a lower-level spell. A spellcaster who lacks a high enough ability score to cast spells that would otherwise be his or her due still gets the slots but must fill them with spells of lower level.

Again - only mentioning that slots are needed to be filled in order to cast a spell. Leading me to believe it is implied - but not explicit - that one can prepare a spell - but not cast it - if placed in an inappropriate slot.

So the question stands: What and where is the rule that explicitly ties spells preparation to spell slots?

Refrence Links:

Arcane Spells (D20)

Wizard (D20)

  • 3
    \$\begingroup\$ Seeing as you could not cast the spell, is the idea to bypass some prerequisite asking for "ability to prepare nth-level spells"? Or why would you want to prepare a spell you can't cast? \$\endgroup\$
    – From
    Dec 11, 2022 at 9:48
  • 1
    \$\begingroup\$ Are you asking whether a character can downcast a spell that is above their caster level using an available slot? \$\endgroup\$
    – StuperUser
    Dec 11, 2022 at 11:35
  • \$\begingroup\$ This isn't a matter of wanting to actually cast the spell just prepare the spell. I was following a logic chain trying to find an exploit regarding another mechanic and ran into the general vagueness and lack of specificity regarding spell slots. So rather than make a hard assumption I thought I would ask smarter people than me to find out what I missed - or if I actually found a potential loophole. If you /can/ prepare without casting - it means another question would be on the way - if you can't, than the loophole dies here. \$\endgroup\$ Dec 11, 2022 at 14:20

2 Answers 2


Remember that preparing spells is starting to cast them:

The act of preparing a spell is actually the first step in casting it. A spell is designed in such a way that it has an interruption point near its end. This allows a wizard to cast most of the spell ahead of time and finish when it’s needed, even if she is under considerable pressure.

(PH, p178, "Spell Selection and Preparation")

Which, in conjunction with the text on Spell Slots on the same page:

The various character class tables [...] show how many spells of each level a character can cast per day. These openings for daily spells are called spell slots.

Tells you that you can only prepare spells for which you have spell slots. Since preparing is casting, if you do not have a slot for a spell, you cannot cast it, and therefore cannot prepare it.

  • 4
    \$\begingroup\$ What is “PG Prem”? That’s a great quote but I don’t recognize the source. \$\endgroup\$
    – KRyan
    Dec 11, 2022 at 14:32
  • 1
    \$\begingroup\$ @KRyan I thought "Player's Guide", but it's of course Player's Handbook, Premium Edition, printed 2012. I wasn't sure if it's just a reprint, so I thought I was being more specific, but should have written "PH Prem". I just double-checked, and the quotes are present on the same page in the original Player's Handbook, so I'll do a quick edit. \$\endgroup\$
    – From
    Dec 11, 2022 at 17:33

There does not appear to be any explicit line that just comes out and says it, but I don’t believe there is any honest reading of these lines that admits any possibility that spells can be prepared outside of those prepared in specific spell slots that the spell can be cast from.

A wizard’s level limits the number of spells she can prepare and cast. […] She can prepare the same spell more than once, but each preparation counts as one spell toward her daily limit.

When preparing spells for the day, a wizard can leave some of these spell slots open. […] [Later], the wizard can fill these unused spell slots.

There is a clear one-to-one-to-one relationship between spell slot, prepared spell, and cast spell. Prepared spells “fill […] unused spell slots.” Your class level “limits the number of spells [you] can prepare and cast,” and when we look at the class description, the only limits indicated there are those found in the spells per day table, which indicate your spell slots. And so on.

Trying to ignore this context and prepare a spell outside of those you have spell slots for is not keeping to the rules as they are written.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .