[RPG] How does casting a cantrip work? Is it different than casting a regular spell


I am a new DM. I do not understand how casting cantrips is supposed to work. For example: is a wizard able to cast Firebolt as an action and then, because Firebolt is a cantrip, cast it again as a bonus action?

Best Answer


Cantrips are spells, just like any other spell. There are 2 differences between a Cantrip and any other spell that has a level of 1 or higher:

  • Cantrips do not use up a spell slot
  • Cantrips can be cast on the same turn that a spell is cast using a bonus action

Cantrips still have casting times denoted just like other spells. For Firebolt


Evocation cantrip
Casting Time: 1 action
Range: 120 feet
Components: V,S
Duration: Instantaneous
You hurl a mote of fire at a creature or object within range. Make a ranged spell attack against the target. On a hit, the target takes 1d10 fire damage. A flammable object hit by this spell ignites if it isn't being worn or carried.
This spell's damage increases by 1d10 when you reach 5th level (2d10), 11th level (3d10), and 17th level (4d10).

You'll notice that it still has a casting time of 1 action.

There do exist ways to change the casting time of spells. For example, the sorcerer's Quickened Spell would allow you to cast two Firebolts on one turn: One as a Quickened spell, and the other as a normal spell.

Quickened Spell
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

There is a complication to this issue, as pointed out to me by Drunk Cynic:

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.

A careful reading of this section reveals that you can only use a bonus action to cast bonus action spells, and you cannot trade standard actions for bonus actions in 5e as demonstrated in this question: https://rpg.stackexchange.com/a/55902/25601