Concentration in D&D 5e (Explained): Checks, Limits, and Common Mistakes
1 April 2026
Concentration is one of the most important rules in D&D 5e spellcasting. It’s the reason you can’t stack every powerful buff at once — and it’s also why taking a hit can swing an encounter.
If you’re building your fundamentals, these help too:
The core rule: one concentration spell at a time
You can concentrate on only one spell at a time.
If you start concentrating on a new spell, the old concentration spell ends immediately.
When do you make concentration checks?
You make a concentration check when you take damage while concentrating.
- The check is a Constitution saving throw.
- The DC is 10, or half the damage taken, whichever is higher.
Example:
- You take 12 damage → DC is 10 (half is 6).
- You take 30 damage → DC is 15 (half is 15).
What breaks concentration (besides failing the save)
Concentration ends if:
- You cast another concentration spell
- You become incapacitated
- You die
Related condition pages:
Common concentration mistakes
- Forgetting the save after damage (this is the #1 one)
- Stacking illegal buffs (two concentration spells)
- Standing in melee with a fragile caster while concentrating
Practical tips to keep concentration
- Get cover and distance.
- Use defensive tools before the hit lands.
- Ask allies to protect you if your spell is “the plan.”
If your party is learning positioning, this pairs well with:
Recommended gear
Helpful table basics. Some links may be affiliate links (we may earn a commission at no extra cost to you). See our Affiliate Disclosure.
- Dice set (7-piece polyhedral) — Fast rolling, less sharing, fewer pauses.
- DM screen — Quick rules reference and cleaner pacing.
- Battle mat / grid map — Movement and AoE become instantly clear.