Many of the best spells — bless, haste, hold person, spirit guardians — need concentration. It is the rule that stops a caster stacking every buff at once, and knowing it well is the difference between a great caster and a frustrated one.
The basics
- Spells that need it say “Concentration” in their duration, for example “Concentration, up to 1 minute”.
- You can concentrate on only one spell at a time. Casting a second concentration spell ends the first.
- You can end it whenever you like, no action needed.
- Casting other, non-concentration spells is fine.
What breaks it
- Taking damage: make a Constitution saving throw. The DC is 10 or half the damage, whichever is higher. Each separate hit needs its own save.
- Being incapacitated or killed.
- Things your DM rules distracting enough, such as a wave crashing over you.
Take 30 damage and the DC is 15; take 8 and it is still 10.
How to keep it
- Raise your Constitution — it helps your hit points too.
- Sorcerers start proficient in Constitution saves, which is why they hold concentration so well.
- Feats: War Caster gives advantage on these saves; Resilient (Constitution) adds proficiency.
- Stay out of melee and behind cover.
Track it on the sheet
The initiative tracker marks who is concentrating so nobody forgets, and your Roleplayer character sheet rolls the Constitution save with one click. Look up any spell in the free spell list and filter by concentration. Rules reference: Casting a Spell.