How it works
Five-part, original Volpedia guide to spells spell slots and concentration, explaining the actual Baldur’s Gate 3 mechanics, common decision points and ways to avoid unnecessary mistakes.
Practical strategy
Follow the chapters in order, then open the related entries when a game rule or location is unfamiliar.
Mistakes to avoid
Do not confuse a suggested route with the only valid story outcome. Check quest warnings before irreversible decisions.
Spells Spell Slots and Concentration: walkthrough
Prepared and learned spell lists
A Wizard can learn spells into a spellbook and then prepare a selection; Sorcerers know a smaller set of spells and use Metamagic; Warlocks use Pact slots that refresh on Short Rest. A character sheet showing a known spell does not prove it is available to cast right now.
Concentration rules and protection
Many combat buffs and battlefield controls require concentration. Only one such spell can remain active per caster; casting a second will end the first, and damage may force concentration saving throws. Protect casters with position and defensive reactions.
Rest resources and reaction casting
Spells such as Shield and Counterspell use reactions, while Healing Word and Misty Step use bonus actions. Plan turn costs so a spell does not consume a resource needed for another vital response.
Plan a spell package for encounters
For a stable party, pair a reliable cantrip with one control spell, one defensive option, one mobility tool and a situational utility spell. Adapt damage elements after examining enemies, then rest before difficult story battles.