What is the casting time of a spell cast using the War Caster feat?

Question

The third benefit of the War Caster feat states (PHB, p. 170):

When a hostile creature's movement provokes an opportunity attack from you, you can use your reaction to cast a spell at the creature, rather than making an opportunity attack. The spell must have a casting time of 1 action and must target only that creature.

However, I am unsure what the actual casting time of a spell I cast using War Caster is. Does it still have a casting time of "1 action"? Or does the casting time change to "1 reaction"?

This matters for things such as the bonus-action limitation on casting additional spells on a turn.

More generally, are the casting time of a spell and the action-economy requirements for casting it different things?

Answer 1

The casting time of a spell is a feature of that spell, unless specifically changed by a feature's wording.

From the Casting a Spell section of the Basic Rules:

Each spell description begins with a block of information, including the spell's name, level, school of magic, casting time, range, components, and duration.

Like a spell's name or level, the casting time of a spell is a feature of that spell. For example, the spell Fire Bolt has a casting time of 1 action, as stated in the spell's description. As a general rule, this will always be true of any given spell, unless a specific feature overrules it. Some features that interact with spellcasting will make that change and some won't.

A feature like the Sorcerer's Quickened Spell Metamagic specifically states that it "change[s] the casting time [of the spell being quickened] to 1 bonus action for [that] casting", so for interactions purposes you would treat that exact instance of the spell being cast as having a casting time of 1 bonus action.

On the other hand, a feature like War Caster makes no mention of changing the casting time of the spell, merely allowing you to cast a spell with a casting time of 1 action using your reaction. Even though you cast the spell using your reaction, it's still considered a spell with a casting time of 1 action.

Interestingly enough, the rule about casting additional spells on the same turn as a bonus action spell uses the phrase "a spell cast with a bonus action", rather than "a spell with a casting time of 1 bonus action", implying that the restriction applies any time a bonus action is used to cast a spell, regardless of the stated casting time of the spell.

Answer 2

You are using your Reaction to cast a spell with a normal timing of 1 Action

Let's break down the situation here and the specific rules around it:

1. Opportunity attacks are Reactions (action cost: Reaction)
2. War Caster lets you use a reaction to cast a spell instead of an opportunity [melee] attack (Action cost: Reaction)
3. In order to do the above, the spell must have a normal action cost of 1 Action (not Bonus Action or Reaction)

The 1 Action defined in War Caster is the requirements for choosing what spells are available, not a statement of the action cost. The action cost is the reaction, that's the opportunity attack. Everything else is just limiting what spells you can pick to use for your spellcasting during your opportunity attack reaction.

The final action cost and timing for the casting a spell using War Caster is just the Reaction. It doesn't cost an Action (Cast a spell), because you normally can't do that as a Reaction. It is a Reaction because it is occurring during the Reaction timing of an Opportunity Attack.

What it does allow you to do is use your Reaction to cast a spell that would normally require an Action.

Answer 3

The casting time is 1 action. War Caster does not change it but bypasses it

The rules for spellcasting on page 202 PHB state:

Each spell description in chapter 11 begins with a block of information, including the spell’s name, level, school of magic, casting time, range, components, and duration. The rest of a spell entry describes the spell’s effect.

So the casting time of a spell is the time that is listed in the spell description.

War Caster

The War Caster feat has this property:

When a hostile creature's movement provokes an opportunity attack from you, you can use your reaction to cast a spell at the creature, rather than making an opportunity attack. The spell must have a casting time of 1 action and must target only that creature

If War Caster changed the casting time of the spell to 1 reaction, it both could not use the spell (as the spell no longer would be a spell with a castig time of 1 action, that it must have), and it would need to say so. Compare the wording to the wording of the sorcerer's Quicken Spell feature that says:

When you cast a spell that has a casting time of 1 action, you can spend 2 sorcery points to change the casting time to 1 bonus action for this casting.

Quicken Spell says it is changing the casting time. War Caster isn't saying that. It instead is bypassing the casting time, allowing you to use your reaction to cast it. The Sage Advice Compendium, under Can you use a melee spell attack to make an opportunity attack explains this:

Each spell has a casting time. (...) The War Caster feat is an example of a feature that does let you bypass a 1-action casting time to cast a spell in place of making an opportunity attack.

This means more generally that the casting time of the spell (which is a property of the spell), and the action required for casting it can be two different things.