Things You Didn’t Know About D&D 5e: Preparing Spells

This is the inaugural article a semi-regular series called “Things You Didn’t Know About D&D 5e”, which will endeavour to keep people informed about rules that tend to be frequently misunderstood or overlooked. You can find the other articles in this series here.


Edit (2018/03/14): I’ve been getting a lot more traffic on this older article, and so I wanted to just let everyone know that it focuses on a single revelation I had one night at 2 a.m years ago (before this website was actually called Dungeon Master’s Workshop). If you are looking for more information about where people typically mess up spell preparation that is written in a more informative way, I would encourage you to check out our article on Multiclass Spellcasting (click here)


Many of you who have perused my posts can probably guess which class is my favourite. If not, I’ll give you a hint: it starts with “w-” and ends with “-izard”. To me, magic is what makes the difference between fantasy and fiction, and the wizard is my idea of the most eminent spellcaster. My very first character was a wizard, and the class will always have a special place in my heart.

Much of my frustration with D&D comes about because I perceive there to be too heavy an influence of the works of Jack Vance. I’ve probably mentioned my hatred for his system of magic in half the posts I’ve made to this blog, if not more. It makes sense in the context of Jack Vance’s world, Dying Earth. Outside of the lore inherent to that world, however, the system is unintuitive and cumbersome.

The problems are inherent to every facet of magic in D&D—why doesn’t a wizard who knows fire bolt automatically know scorching ray, when they’re pretty much the same thing and he’s done the first one dozens or even hundreds of times? Because Jack Vance. Why can’t a wizard who knows control water use a very minor manifestation of that magic to splash someone with the contents of their waterskin without having to burn a 4th-level spell slot? Because Jack Vance. Why do we even have named spells (especially dumb ones like prismatic spray) which are always cast the same way, as opposed to a pool of magic with which a caster might shape each individual spell? Because Jack Vance.

It was to my great delight to find that the Fifth edition wizard no longer forgot spells upon casting them, as had been the case in 3rd edition where classes that prepare their spells had to prepare them to a specific spell slot. No longer did wizards have to prepare fireball multiple times in order to cast it more than once, they simply had to have it on their list of prepared spells. Additionally, spells in Fifth Edition could be cast using any slot of the spell’s level or higher, meaning that you could still cast a spell if you had burned all the spell slots of that spell’s level. While the spell slot mechanic had not been thrown out entirely, it was still a victory. It was like we had finally told Jack Vance to get his grubby fingers out of our fantasy.

However, I recently discovered that there was another benefit to this that I had overlooked in my excitement: you no longer have to prepare your spells every day!

To save you the effort of opening up your book, I’ll give you the rules for preparing and casting spells, as found on page 114 of The Player’s Handbook:

The Wizard table shows how many spell slots you have to cast your spells of 1st level and higher. To cast one of these spells, you must expend a slot of the spell’s level or higher. You regain all expended spell slots when you finish a long rest.

You prepare the list of wizard spells that are available for you to cast. To do so, choose a number of wizard spells from your spellbook equal to your Intelligence modifier + your wizard level (minimum of one spell). The spells must be of a level for which you have spell slots.

For example, if you’re a 3rd-level wizard, you have four 1st-level and two 2nd-level spell slots. With an Intelligence of 16, your list of prepared spells can include six spells of 1st or 2nd level, in any combination, chosen from your spellbook. If you prepare the 1st-level spell magic missile, you can cast it using a 1st-level or a 2nd-level slot. Casting the spell doesn’t remove it from your list of prepared spells.

You can change your list of prepared spells when you finish a long rest. Preparing a new list of wizard spells requires time spent studying your spellbook and memorizing the incantations and gestures you must make to cast the spell: at least 1 minute per spell level for each spell on your list.

If you read closely, there are some significant words missing from this section. I’ll quote them from the Wizard entry back in 3.5 (emphasis mine): “A wizard must study [their] spellbook each day to prepare [their] spells”.

For new players who didn’t play previous editions, back in the halcyon days of Third Edition, if you were wakened in the morning by a pack of orcs breaking down your door and you didn’t have any attack spells left from the day before, you had to study your spellbook for at least 15 minutes in order to prepare magic missile or fireball to destroy them. And gods save you from losing your spellbook—that would mean you’d only have access to spells you still had prepared and whatever else you have in scroll form!

What Fifth Edition has changed is that your prepared spells automatically refresh when you finish a long rest. It’s only if you didn’t have a spell prepared the previous day that you have to spend time preparing it. For example, wanting to swap out fireball for another spell you know, such as scorching ray, would require that you spend time studying your spellbook to refamiliarize yourself with the arcane formula of that spell. If you prepared a spell yesterday, it’s still prepared today, even if you cast it.

Put in other words: losing your spellbook doesn’t doom you to effectively become level 0 when you use up your remaining prepared spells. Now you just lose the spells you didn’t have prepared when you lost the book.

And it’s not just this way for wizards. No spellcasting class—not clerics, not druids, not paladins, no one—has to “re-prepare” their spells every day; they only have to spend 1 minute per spell level adding a new spell to their list of prepared spells for the day, swapping another spell out for each new one.

A consultation of Reddit confirmed that I was reading the rules correctly with this new revelation, and that many other people were also surprised at the removal of the daily preparation mechanic. By posting this clarification, I hope to inform others who have been handling this class incorrectly.

Happy adventuring!

12 thoughts on “Things You Didn’t Know About D&D 5e: Preparing Spells”

  1. Hey, I have a question! I wonder if you could clear up how preparing spells and exchanging spells work during leveling up for multiple classes. Or where I could read up on it. I have a druid, cleric, bard and warlock spellcasters and they want to change the spells/cantrips they put initially, how would I go about this?

    1. Hi Karolis,

      Thanks for your question!

      Each class that can cast spells has a description of the feature that grants that ability. Most of the time it’s called “Spellcasting”, but warlocks have “Pact Magic”. If you read through each class’ feature, it will tell you how they learn and prepare spells. Clerics, for example, get to prepare any cleric spell for which they have spell slots and can swap all of their choices every single day. Bards, on the other hand, know a certain number of spells and can only replace spells known when they gain a level in the bard class.

      And if any of your characters are multiclass spellcasters, remember that you always learn and prepare spells for a class as though you only had levels in that class. This means that if you have 16 levels in the cleric class and you take one (1) level of sorcerer, you can’t learn the 9th-level spell wish as a sorcerer spell because you only count as a 1st-level sorcerer when it comes to picking your sorcerer spells, and a 1st-level sorcerer only has 1st-level spell slots.

      As a final note, there is no RAW mechanic to swap out cantrips. If you would like to let your players replace cantrips, you will have to come up with a house rule. Personally, I allow my players to swap them out when their characters gain a level. Jeremy Crawford will tell you that cantrips are meant to be permanent choices since they grow in power with the character, but last I checked I’m not Jeremy Crawford and so I can do what I want, and so can you. If you want to let your players swap cantrips, do it.

      Best,
      – the Archmage

    1. In some circumstances, yes. It means you can cast any spell you have prepared as long as you have an unexpended spell slot of that spell’s level or higher.

      For example, if you are a 1st-level wizard with Intelligence 20 (+5) and you prepare detect magic, feather fall, mage armour, magic missile, shield, and thunderwave, then you can cast any of those spells twice (because you have two spell slots). If you want to cast magic missile twice, that’s fine. If you want to cast mage armour and thunderwave, that’s also fine. Any prepared spell.

      But when you reach 3rd level as a wizard and get access to 2nd-level spell slots, you can’t cast a 2nd-level spell using a 1st-level spell slot. You can only ‘upcast’ by casting a lower level spell with a higher level slot (many spells actually get better when you do this).

      Best,
      the Archmage

  2. I have a question about the prepared spells. When I read it, to me it reads like when you take a long rest to automatically regain your spell slots but the preparation for what spells you prepare takes place after your long rest and is separate, especially because it’s says you have to spend additional time to prepare the spell. To me it seems, after a long rest you can choose to prepare a new spell any time after, as long you prep for the 1 min per level. Is this the case? Could I leave my list “unfinished” after my long rest come across a problem and then prepare the appropriate spell to take that slot? To me this makes more sense than a wizard who wakes up everyday and immediately has guess what kind of spells he needs.

    1. Hi Jonathan,

      You change your list of prepared spells when you finish a long rest, not a few hours later.

      It bothers me, too, that the wizard who has their spellbook on hand can’t sit down during a quiet respite and swap spells. It’s not like it has anything to do with the state of mystical energies at a specific time of day like dawn or dusk; whether a long rest ends at 8 a.m. or at 2 p.m. doesn’t seem to matter.

      It is clearly a holdover from Third Edition, when you prepared spells to spell slots and you got spell slots back at the end of a period of 8 hours’ rest (when your mind was still fresh or whatever). A wizard in Third Edition who blew all of their spells the day before would have to spend an hour (after an eight-hour rest) simply to sit with their spellbook and prepare new spells to each spell slot (this magic missile spell to this 1st-level spell slot, that fireball spell to that 3rd-level spell slot, etc.), or proportionately less time if they only have to prepare a few spells because they still had some prepared from the day before (down to a minimum of 15 minutes to prepare at least one spell). Note that preparing a spell in Third Edition involved partially casting it, taking the raw magical power and putting it into a specific shape ready to be unleashed with the right trigger.

      Interestingly, this process of preparing your spells for the day did not have to be done all at once in Third Edition if you were a wizard. You could leave some spell slots open and prepare spells again later in the day as often you liked, time and resources permitting. You couldn’t ditch already prepared spells until you finished another long rest (though the ‘long rest’ mechanic didn’t come around until that edition), but a 15-minute rest would let you prepare a number of spells up to a quarter of your total spell slots. Other spellcasters didn’t have this same freedom. Clerics, for example, prayed for their spells daily at dawn or dusk, though they had certain tricks to add versatility, such as being able to spontaneously drop prepared spells to cast cure wounds.

      Perhaps limiting spell preparation to the end of a long rest across the board was the best way the developers thought to even the playing field in Fifth Edition’s paradigm. That said, you could easily devise a houserule to address this. Perhaps at the end of a short rest, someone who prepares their spells could swap a number of them equal to their spellcasting ability modifier? Just a thought.

      Best,
      the Archmage

      1. Just as a tangent to my above point about the differences between Third and Fifth Edition, Fifth Edition has really solidified the “eight-hour adventuring day” that people tended to gripe about in Third Edition. At least, it did for arcane spellcasters.

        Yes, various classes have spell slot recovery methods like Arcane Recovery (wizard) and Natural Recovery (druid), but your spell slots are very much a daily allotment of power because they are replenished at the end of a long rest and you only can benefit from one long rest per day. Your spell slots are therefore that day’s power.

        By contrast, in Third Edition you could get spell slots back throughout the day. There was, to borrow video game terminology, an eight-hour cooldown on each spell slot. However, there was no restriction on the number of eight-hour rests you could take in the same day. An arcane spellcaster could get in a fight at 9 a.m., spend the next eight hours in uninterrupted rest, and prepare new spells again after 5 p.m. to continue your adventure. Getting real uninterrupted rest in most dungeon environments was, of course, damn near impossible, but you could retreat to some sanctum and come back the same day.

        Again, this only applied to arcane spellcasters. Divine spellcasters still had to pray for spells at a certain time of day (dawn, noon, dusk, whatever it may be), which meant that while they could take eight hours’ rest at any point, they wouldn’t get their magic back.

        The Archmage

  3. In the older TSR editions of D&D / AD&D, you don’t forget any spells when you sleep: every spell that was in your head when you fell asleep is still there when you wake up, ready to cast on a moment’s notice.

    As such, you don’t always need to study your spellbook every day: if you don’t cast any spells on a given day, you’re entirely able to just keep them in your head for tomorrow.

    1. Hi Queen,

      Thank you for your comment!

      I do think you might have misread the article if you are attempting to correct me on this point, as I never said you instantly forget all your spells when you fall asleep. The difference I was pointing out with Fifth Edition is that you get back expended spells when you finish a long rest without having to study your spellbook.

      To put it in other words, while in v3.5 you had to re-prepare any fireball you cast yesterday (assigning it to a specific spell slot), in Fifth Edition you just have to have had fireball on your list of prepared spells from the day before—there’s no need to reassign it because spells are no longer prepared to a specific slot.

      Best,
      the Archmage

  4. I am a bit confused by the statement “No spellcasting class—not clerics, not druids, not paladins, no one—has to “re-prepare” their spells every day; they only have to spend 1 minute per spell level adding a new spell to their list of prepared spells for the day, swapping another spell out for each new one.

    Does this mean if I am a lvl 1 wizard with Int modifier of +3, and after my long rest I prepared Burning hands, Charm Person, Magic Missile and Shield, but as the day goes on find I need Sleep to avoid a guard, I can spend 1 minute to swap in Sleep for one of those four I had prepared? Or would I need to wipe clean and use 1 minute for each of the four 1st lvl spells? Or can this still only be done at the end of a long rest?

    1. Hi Eseles,

      The statement means just what it says. If you prepared the fireball spell yesterday, you don’t have to prepare it again today. It’s still prepared.

      If you don’t have sleep prepared and you want to prepare it, you can do so at the end of a long rest. You may have to drop a different spell, though, if you are full up on the number of spells you can prepare.

      This is different than in previous editions, where on day 1 you might prepare fireball three times to three 3rd-level slots and use two of them, and when you woke up on day 2 you would have to re-prepare those fireballs that you used.

      Best,
      the Archmage

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