An argument came at our table about the duration of the Shield spell, the crux of the matter being the interpretation of the words "until the start of your next turn".

From the Shield spell description (PHB, p. 275, emphasis mine):

Duration: 1 round [...]

An invisible barrier of magical force appears and protects you. Until the start of your next turn, you have a +5 bonus to AC, including against the triggering attack, and you take no damage from magic missile.

Two cases were made :

  1. When cast using a reaction, the Shield spell lasts until the caster's turn in the initiative. Thus, if the spell is triggered by a monster attacking with an initiative of 20 and the caster acts at 19 (beginning it's turn), the spell will have a very short duration. On the other hand, if the monster triggers the spell at 20 and the caster's initiative is 1, the spell would last almost for the entire round, protecting the caster against every other monsters acting after the 1st.

  2. When cast using a reaction, the Shield spell lasts until the NEXT caster's turn, which means the spell triggered at 20 would last through the caster's turn (19) and then go on until the beginning of his NEXT turn (initiative 19, round 2). That creates a situation where the caster is protected against Monster 1, then all other monsters in the round, then again against Monster 1, since the caster's NEXT turn still hasn't begun when it acts in the second round.

As I argued that the same instance of the spell couldn't protect the caster from the same Monster two rounds in a row, my friend assured that my ruling (#1) would make the spell so weak that, considering the spell slot economy, nobody would ever want to use it.

As a sidenote, the stated duration of the spell (1 round) could be misleading, since it would imply that it MUST last an entire round (as it would if the spell was cast from a scroll or a magic item). Maybe the wording "up to 1 round" could have been more accurate?

Which reading of the spell is correct?

  • 3
    \$\begingroup\$ Consider that the Shield spell is cast after you determine if you were hit or not, it's definitely not as weak as it sounds to your group. \$\endgroup\$
    – JPicasso
    Commented Feb 13, 2017 at 13:28
  • \$\begingroup\$ That second ruling has the same issue though. The slow wizard would still get the shield spell for longer, and would essentially get two full rounds of the bonus while the fast wizard (init 19) still only gets one round. The problem isn't how long the spell lasts, it is when it is getting cast relative to the wizard's turn \$\endgroup\$
    – D.Spetz
    Commented Feb 13, 2017 at 20:46

3 Answers 3


Your ruling is correct.

The effect of shield ends at the start of your next turn, which is the next turn you take. Your ruling #1 is correct.

There are many spells which have a listed duration of 1 round, 1 minute, 1 hour, or so on with a trigger listed in the text that causes the spell to end before that duration is reached. Although we might prefer the spells listed their duration as "up to 1 round," "up to 1 minute," or so on, the implication is indeed that that duration is a maximum limit. So the listing of a 1 round duration does not contradict the listing of an ending condition triggered by the start of your next turn.

Justifications for this ruling.

Each time a creature's turn ends, the next creature's turn begins. So your next turn is the occurrence of your creature acting following the last turn you took, whether or not a full round of turns has elapsed. This is the logical consequence of Jeremy Crawford's clarification on the flow of turns (see this tweet):

When your turn ends, the next person's turn starts.

Without going into a needlessly formal proof using the well-ordering principle, Crawford's statement establishes that your next turn is defined by the ordering of the turns as they elapse, not by the quantity of turns that have elapsed.

Also, a stated design intent in 5e is that words should be read according to their idiomatic meanings. In English, "your next turn" means "your next turn," not "your next turn or after 1 round, whichever is sooner." The simplest interpretation is both intended and correct.

Why it is a good Level 1 spell.

Your friend's reasoning that shield is weak is fairly unsound, and ruling #2 is neither necessary nor supported by the rules.

It's not that you're losing future time on the duration of the spell if you cast it too late in the round before the start of your next turn. You are de facto protected from all attacks for a whole round between any one of your turns and your following turn by (A) the reaction casting of shield mid-round, by (B) the ongoing spell effect after that until your following turn, and by (C) the threat of what we might call "potential shield" before it was actually cast (since before you cast shield there were probably no attacks that targeted you anyway and for the entire round enemies may have chosen not to attack you due to knowledge that you possess the potential to cast the shield spell).

In my experience in games in which I have been a player or a DM, squishy casters like Wizards have used it at least once but usually twice per session. Now note that a +5 bonus to AC is more than what any mundane armor or rare magical armor can confer and it can often be relied upon for most of the attacks that target you for a whole encounter due to the spell slot and action economy. You even get to wait and see if an attack would hit you before you choose to use it.

Therefore, I assert that it is a plenty powerful and comparable Level 1 spell with good utility. It does not need to be fixed. Stick with your correct ruling.

  • 2
    \$\begingroup\$ Honestly I think what makes the text confusing is the use of "your next turn". If someone were to say they were doing something "next Tuesday" it probably wouldn't mean tomorrow (if said on Monday). Its difficult to be sure from wording alone if it means next in that sense or immediately next. Though the rest of your explanation is excellent and largely disambiguates that, +1 \$\endgroup\$
    – Vality
    Commented Feb 13, 2017 at 20:02
  • 3
    \$\begingroup\$ I think it's closer to talking about "next week." Suppose that it is Saturday and I say "next week." I'm probably talking about the week that starts the immediately following Sunday, not the week that comes after that one. \$\endgroup\$ Commented Feb 13, 2017 at 20:16

The shield spell ends at the beginning of the caster's next turn, even if that next turn is this round. To maximize your newfound AC you want to use shield as soon as possible after you've taken a turn.

  • 3
    \$\begingroup\$ I agree with your conclusion, but this answer lacks support. It needs some kind of reference. As it stands the OP wants more justification for why this must be the case. \$\endgroup\$
    – Adam
    Commented Feb 13, 2017 at 1:18
  • 2
    \$\begingroup\$ @Adam The support is already in the spell's text. The question was "Which reading of the spell is correct", and this answer is correct. If OP is looking for some sort of justification, perhaps another answer might come up. \$\endgroup\$
    – daze413
    Commented Feb 13, 2017 at 2:18
  • 1
    \$\begingroup\$ @daze413 the best stack answers have justification. This answer does not contain justification in its body. I'm simply suggesting a way to improve it, since few people are going to attempt another answer because this one is so highly rated. \$\endgroup\$
    – Adam
    Commented Feb 13, 2017 at 2:22
  • 1
    \$\begingroup\$ I would be happy to update the answer to include justification if anyone had any specific suggestions. I personally have not found any specific text that's relevant beyond simply reading the spell as written. If there is some to point to I'm happy to do so. \$\endgroup\$ Commented Feb 13, 2017 at 2:30
  • 1
    \$\begingroup\$ @GarrettRooney That would make the answer more complete, yes. Perhaps something about how it should be a part of the decision whether to cast Shield knowing that your turn is coming up next. Do you avoid that damage now or try to gamble? You might also go into how it doesn't matter if you're going against a solo opponent, and how the Shield spell would only seem unfair only in this very specific case. \$\endgroup\$
    – daze413
    Commented Feb 13, 2017 at 4:38

Shield Spell 5e

An invisible barrier of magical force appears and protects you. Until the start of your next turn, you have a +5 bonus to AC, including against the triggering attack, and you take no damage from magic missile.

Rule #2 is literally backed up by the spell even saying yes and even against the attack that triggered it. AKA your "it can't work against 2 attacks". A round is literally happening all at once. So if I cast it this turn it lasts till my next turn starts and yes cover even that attack or monster that would be 2x as stated even the trigger.

This creates a balance between the caster who cast shield vs., the monster who goes right before it. Or the one who goes right after in the initiative.

In Rule #1 e.g. mob1,
"Shield Caster"
if you cast shield vs mob 4 it protects you from every mob but if you cast it against mob3 it fizzles and goes out of existence.

  • 5
    \$\begingroup\$ As it’s currently written, your answer is unclear. Please edit to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers in the help center. \$\endgroup\$
    – Community Bot
    Commented Mar 27, 2022 at 8:10
  • 1
    \$\begingroup\$ Can you back this answer up with anything? Your insistence that the number of mobs it protects against being different depending on when you cast it not being how it works just because you feel that it is weird is not a valid answer. Technical questions should have technical answers backed up by evidence (rules written in books, statements from developers, etc.). \$\endgroup\$ Commented Mar 27, 2022 at 15:19
  • \$\begingroup\$ As to your point, no casting it on mob3 would not fizzle, it would protect you against mob 3, as it specifies it protects against the triggering attack. If mob 3 had multiattack, and you used it on mob 3's first attack, it would protect you against all of mob 3's attacks. It would then end on your turn. This is in fact how it works. If you use it earlier in the turn, the +5 lasts through more mob's turns \$\endgroup\$ Commented Mar 27, 2022 at 15:21

You must log in to answer this question.

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