Is it possible to cast multiple spells per turn?

Question

Never had an issue with spellcaster scaling until today. A player in the group claims he can cast Eldrich Blast twice on his turn. Once as an action, and a second time as a bonus action since it is a cantrip. Allowing him to shoot 4 beams for a d10 each (he's 5th level so 2 beams per cast). This seems vastly stronger than anyone else's max 2 attacks. After the session which ended early with many players angry this player ruined all encounters, there was much talk of re-rolling into all caster party. One wanting to do the same with a wizards Firebolt spell as a bonus every turn, others still browsing.

So, is it possible for a caster to cast multiple spells in 1 turn? From what I was quoted from the PHB, it's possible to cast any spell as an action, then cast a second spell; as long as the bonus action spell was a cantrip with a cast time of 1 action? So 99% of all cantrips? Please tell me this is wrong, because I feel that if anyone else does this our melee characters will never see a fight again before the casters nuke them down.

Answer 1

You were quoted the rules incorrectly.

First, Eldritch Blast has a casting time of 1 action (PHB p.237). You've only got one action on your turn, so you can only cast Eldritch Blast once. ("Off the shelf," that is. There are features, like the Sorceror's Quickened Spell, Action Surge, or even time stop that might change this.)

Boom. That's it. They can't cast a second eldritch blast as a bonus action, because the casting time of eldritch blast isn't "1 bonus action." (Compare with, say, healing word.)

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But that's understandable.

It is possible for a caster to cast a spell as a bonus action and another as an action in one turn; the conditions are described exactly on PHB p.202:

• one spell has casting time of 1 bonus action,
• you've not used a bonus action for anything else this turn (because you can only take one bonus action per turn),
• the other spell is a cantrip,
• the other spell has a casting time of 1 action.

D&D is a great game in many ways. It has never, in my experience, been presented in its published materials in a way that makes sense to someone who doesn't already know the game. One player misunderstood something, and no other players nor the GM knew the rule well enough to course-correct mid-session.

That's fine. You now know. Alert your group as soon as possible and be ready for a group conversation about whether this should now be a table-rule, or will this just have been one shining moment in 'Lock's career. "Hey, guys, remember that one day when I was in beast-mode? My patron must have been having me on!"

Answer 2

It appears the player has garbled the rules on Bonus Action casting time spells (PHB p.203):

Bonus Action A spell cast with a bonus action is especially swift. You must use a bonus action on your turn to cast the spell, provided that you haven’t already taken a bonus action this turn. You can’t cast another spell during the same turn, except for a cantrip with a casting time of 1 action.

The spell cast using the Bonus Action must have a casting time of 1 Bonus Action. There are very few of these and Eldrich Blast is not one of them.

A sorcerer can use metamagic to Quicken a 1 action spell to a 1 bonus action casting time and this would allow the double combo the player wants: just not to Warlocks.

Answer 3

No. You can only cast a spell as a bonus action if the casting time in the spell description says "1 bonus action." Eldritch blast does not. If you cast a bonus action spell, the only other spell you can cast that turn is a cantrip. So, if he casts Hex, he can still cast Eldritch Blast that same turn, but not another leveled spell. This is the rule to which your player was referring (and misinterpreted).

There are features of other classes that can affect casting times, but not in the warlock class.

Answer 4

Let's start with the PHB definition of a bonus action (pg. 189):

Various class features, spells, and other abilities let you take an additional action on your turn called a bonus action.

So you can only use a bonus action when something says that is a bonus action.

Let's have a look at the bonus action description under "Casting Time":

A spell cast with a bonus action is especially swift. You must use a bonus action on your turn to cast the spell, provided that you haven't already taken a bonus action this turn. You can't cast another spell during the same turn, except for a cantrip with a casting time of 1 action.

So only spells with a casting time of "bonus actions" can be used as a bonus action (healing word, sanctuary and spiritual weapon are examples of this). But if you cast one of this spells, you can only cast a cantrip with your standard action.

So you can't cast a spell with a casting time of "1 action" as a bonus action, unless special circumstances reduce the casting time to a "bonus action", like the sorcerer Quickened Spell metamagic option.

Answer 5

I believe you are misreading what the rules say about casting spells with a bonus action. From the SRD:

A spell cast with a bonus action is especially swift. You must use a bonus action on your turn to cast the spell, provided that you haven’t already taken a bonus action this turn. You can’t cast another spell during the same turn, except for a cantrip with a casting time of 1 action.

It do not say that you can cast a cantrip with a bonus action on your turn. It says that if you cast a spell that has a cast time of a bonus action (eg, Healing Word), you can only cast another spell with your action if it is a cantrip.

Answer 6

No. Here is what the Sage Advice Compendium (2019) has to say:

(For those unaware, the SAC is list of rules clarifications written by the D&D game designers. As sometimes the Rules as Written are unclear, the SAC provides the developer’s Rules as Intended.)

Can a bonus action be used as an action or vice versa? For example, can a bard use a bonus action to grant a Bardic Inspiration die and an action to cast healing word?

No. Actions and bonus actions aren’t interchangeable. In the example, the bard could use Bardic Inspiration or healing word on a turn, not both.

As Eldritch Blast has the casting time of one action, it can not be cast as a bonus action. As stated above, actions and bonus actions aren’t interchangeable, the player could only cast Eldritch Blast with their action.

However, the Sage Advice Compendium also says this:

Is there a limit on the number of spells you can cast on your turn?

There’s no rule that says you can cast only X number of spells on your turn, but there are some practical limits. The main limiting factor is your action. Most spells require an action to cast, and unless you use a feature like the fighter’s Action Surge, you have only one action on your turn.

If you cast a spell, such as healing word, with a bonus action, you can cast another spell with your action, but that other spell must be a cantrip. Keep in mind that this particular limit is specific to spells that use a bonus action. For instance, if you cast a second spell using Action Surge, you aren’t limited to casting a cantrip with it.

Firstly, this further confirms that Eldritch Blast can not be used twice, though you can cast it and a spell with a casting time of a bonus action as Eldritch Blast is a cantrip. Secondly, this states that you could cast Eldritch Blast twice per turn if you had two actions per turn.

Finally, there is a section about casting reaction spells:

Can you cast a reaction spell on your turn?

You sure can! Here’s a common way for it to happen: Cornelius the wizard is casting fireball on his turn, and his foe casts counterspell on him. Cornelius also has counterspell prepared, so he uses his reaction to cast it and break his foe’s counterspell before it can stop fireball.

Now, whilst Eldritch Blast does not have any reactions attached to it in it’s description, the War Caster feat says:

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

Theoretically, this means you could cast Eldritch Blast using your action then, if the creature moves, you could use it again, but only on the creature that moved. In this way, you could fire 4 Eldritch Blast beams at 5th level in a single turn (or 8 in one turn at 17th level), but half of them can only hit a single target, and only if their movement provokes an opportunity attack from you and you have the War Caster feat.

It's even possible that, by multi-classing and using feats, you could use Eldritch Blast even more times per turn. For example, combining Action Surge and the War Caster feat, you could: use an action to cast Eldritch Blast, Action Surge, use your second action to cast Eldritch Blast, opportunity attack is provoked, use your reaction to cast Eldritch Blast. A character who was a 5th-level Warlock and 2nd-level Fighter could fire 6 beams in a single turn this way; a 17th-level Warlock and 2nd-level Fighter could fire 12 beams a turn using this method.

Answer 7

You can:

1. Cast a spell as an action as well as a reaction spell during your turn.

or

2. Cast a cantrip as an action, and either a bonus action spell or a reaction spell during your turn.

The rules on bonus action spells state:

A spell cast with a bonus action is especially swift. You must use a bonus action on your turn to cast the spell, provided that you haven't already taken a bonus action this turn. You can’t cast another spell during the same turn, except for a cantrip with a casting time of 1 action.

The rules for bonus action spells, which lack any explicit exception, explicitly prohibit the casting of any other spell in the same turn as a bonus action spell except for a cantrip with a casting time of 1 action. Thus, reaction spells and bonus action spells are mutually exclusive during your own turn this way; you can't cast 3 spells on your own turn. You cannot cast Shocking Grasp, miss, cast Expeditious Retreat, move, and cast Shield in response to an opportunity attack, as this violates the bonus action rule, because it's still the same turn.

Traditionally, this isn't an issue as most are familiar with the cantrip + bonus action spell option, but using a reaction to cast a spell on your own turn can't be done if you've already cast a bonus action spell first, or prohibits the use of a bonus action spell for the rest of your turn. This also means you cannot counter-Counterspell to protect any bonus action spell (such as Quickened spells), as this invokes the same bonus-action restriction.