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From RAW, it's clear that a character can ready a spell that has a casting time of 1 action and release the spell when the trigger occurs or directly after the trigger finishes:1 Provided, that the character's concentration is not broken.2

Is there any time limit (rounds, turns, etc.) on how long a character can hold a readied spell as long as concentration is maintained?

Example 1: How long can I wait just around the corner with a readied lightning bolt having a trigger of "I release the spell when a creature (or anything) comes around the corner"?

Example 2: How long can a back row spellcaster hold a readied dimension door with a trigger of "if an enemy breaks through the front line, then I release the spell"? Which would allow the spellcaster to move and attack with a ranged weapon each turn with an escape plan. ("Normal activity, such as moving and attacking, doesn't interfere with concentration." PBR, p. 80; PHB, p. 203)


  1. Under "Adjudicating Reaction Time" in the Dungeon Master's Guide:

    Use this rule of thumb: follow whatever timing is specified in the reaction's description. For example, the opportunity attack and the shield spell are clear about the fact that they can interrupt their triggers. If a reaction has no timing specified, or the timing is unclear, the reaction occurs after its trigger finishes, as in the Ready action. [Emphasis added] (DMG, p. 252)

  2. According to the Player's Basic Rules and Player's Handbook:

    When you ready a spell, you cast it as normal but hold its energy, which you release with your reaction when the trigger occurs. To be readied, a spell must have a casting time of 1 action, and holding onto the spell's magic requires concentration. If your concentration is broken, the spell dissipates without taking effect. For example, if you are concentrating on the web spell and ready magic missile, your web spell ends, and if you take damage before you release magic missile with your reaction, your concentration might be broken. [Emphasis added] (PBR, p. 72; PHB, p. 193)

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The recently released Player's Handbook Errata clarifies this:

Ready (p. 193). You have until the start of your next turn to use a readied action.

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Until the end of the round.

The Ready action specifies in its description that you can only hold your action until later in the round. (PHB, p. 193)

The notes about concentration and the breaking thereof are additional to this limit, not a replacement thereof — it specifies that the normal Ready-Reaction timing stays the same when it says

you cast [the spell] as normal but hold its energy, which you release with your reaction when the trigger occurs.

There are no other notes about Readying spells being different than Readying any other action, so they get no special treatment and expire like any other Readied action.


This is ripe for house ruling though. I imagine it will be a relatively common house rule, either on purpose or by accident of not noticing the limit in the first place.

It would have a significant impact on party tactics though (as your dimension door example demonstrates), and will likely be polarising between different groups or between players used to one way joining groups with DMs used to running it the other way.

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  • \$\begingroup\$ Specifically the part that says, "you can take the Ready action on your turn so that you can act later in the round using your reaction"? \$\endgroup\$ – sadaqah Jan 17 '15 at 5:04
  • \$\begingroup\$ @sadaqah That's the bit, yes. \$\endgroup\$ – SevenSidedDie Jan 17 '15 at 5:20
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p 192 of the PH say

When you take your action on your turn, you can take one of the actions presented here ...

p 193 says

When you ready a spell, you cast it as normal but hold its energy, which you release with your reaction when the trigger occurs. To be readied, a spell must have a casting time of 1 action, and holding onto the spell’s magic requires concentration (explained in chapter 10).

So, you take ready (a spell), the trigger does not occur and your turn rolls around again. So, what can you do?

As written, the "energy" is not released so to my mind I can see several options:

  1. Its gone - too bad
  2. You could take Ready again with the same trigger
  3. ... or a different trigger; possibly including the trigger "Now!" (equivalent to 4.)
  4. You could take the "Cast a Spell" action to release the energy
  5. You could take any other action and so long as you maintain concentration the spell is sitting like a malignant toad in your brain ready to be used on some future action ("Cast a Spell" or "Ready").

Personally, I would rule any or all of 2-5 as No 1 would pretty seriously discourage the use of Ready to cast a spell and none of the others seem overpowered - essentially you have given up an action and a spell slot and concentration for some nebulous future benefit. Contrast this with Ready vis a vis any other action which only makes you give up your action.

The advantage of this is it is readily applicable in a non-combat situation, the same mechanics are in play, just implicitly rather than explicitly, so you can hold the spell until you use it or your concentration breaks (voluntarily or involuntarily); effectively taking Ready round after (implicit) round.

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  • \$\begingroup\$ For non-cantrips, would you say that the spell slot is used when the spell is readied or when it's released? \$\endgroup\$ – SevenSidedDie Jan 18 '15 at 2:10
  • \$\begingroup\$ NRBH but I would say it is when the spell is cast, "readying" means pre-planning the (re)action you will take in response to the trigger - it is not the action itself. \$\endgroup\$ – Dale M Jan 19 '15 at 0:31
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    \$\begingroup\$ @SevenSidedDie I interpreted it the opposite way: "you cast it as normal but hold its energy." Casting as normal involves expending a spell slot. \$\endgroup\$ – detly Jul 8 '15 at 6:39
  • \$\begingroup\$ @detly I have reviewed the PHB and I agree with your interpretation. \$\endgroup\$ – Dale M Jul 8 '15 at 6:58

protected by doppelgreener Aug 3 '18 at 7:36

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