What Breaks Concentration in 5e? [DnD Quick Guide]

Concentration can be broken in a few ways in DnD 5e:

Taking damage: Whenever you take damage while concentrating on a spell, you must make a Constitution saving throw to maintain concentration. The DC for this saving throw is equal to 10 or half the damage you took (rounded down), whichever is higher.
Casting another concentration spell: If you start casting a new concentration spell, the current spell you’re concentrating on immediately ends.
Using a concentration feature: Some subclasses have features that read “as if you were concentrating on a spell” — using one of these immediately ends concentration on a spell or other such feature (Jeremy Crawford). The same goes for magic items that cast spells that require concentration to maintain.
Being incapacitated or killed: If you become incapacitated or die, you automatically lose concentration on any spells you were maintaining. Becoming paralyzed, stunned, unconscious, or petrified also causes you to become incapacitated, thus ending your concentration.
Environmental effects: The DM can rule that something like “a wave crashing over you while you’re on a storm-tossed ship” requires a DC 10 concentration check. Similar circumstances could include an earthquake, a strong gust of wind, or being swept away by a forceful current (PHB 203).
Some spells: Some spells have direction interactions with concentration:
- Sleet Storm. 3rd-level Conjuration spell that forces concentration checks (DC is spell save DC of caster) for any caster in the area who’s currently concentrating on a spell.
- Earthquake. 8th-level Evocation spell that forces concentration checks (DC is spell save DC of caster) for any caster in the area who’s currently concentrating on a spell.
- Storm of Vengeance. 9th-level Conjuration spell that forces regular environmental factor concentration checks (DC 10) from rounds 5-10 of being conjured.
Casting a spell with a casting time longer than 1 action, including rituals. “When you cast a spell with a casting time longer than a single action or reaction, you must spend your action each turn casting the spell, and you must maintain your concentration while you do so” (PHB 202).