Spellcasting Basics
Spell slots are consumed to cast spells; spell save DC = 8 + ability modifier + proficiency bonus. Concentration allows only one active ongoing spell.
Spellcasting is how magic-using characters interact with the world through spells.
Spell slots: Most casters use spell slots — a pool of energy consumed when casting a spell. Slots are categorized by level (1st through 9th). Casting a spell typically consumes a slot of the spell's level or higher.
Cantrips: Level-0 spells with no slot cost, castable at will. Cantrip damage scales with character level.
Spell attack rolls: Some spells require an attack roll: 1d20 + spellcasting ability modifier + proficiency bonus.
Spell save DC: 8 + spellcasting ability modifier + proficiency bonus.
Spellcasting abilities by class:
Concentration: Some spells require concentration to maintain. You can only concentrate on one spell at a time. Taking damage requires a Constitution save (DC 10 or half the damage taken, whichever is higher) to maintain concentration.
Ritual casting: Spells with the ritual tag can be cast without spending a spell slot, but take 10 extra minutes.