Dungeons and Dragons inspired the CRPG Baldur’s Gate 3 to such a degree that the game is basically a 1:1 translation. There are a bunch of mechanics that 5E players will know well. If you’ve never played D&D before, there may be things you don’t understand. The spellcasting in particular is kind of hard to grasp. Spells bring out a bunch of options for combat and other encounters. but with some spells that have requirements to cast them. To maintain effects for some spells, you need to maintain Concentration in Baldur’s Gate 3.
The system is a direct copy from 5E, meaning that any damage you take or other disruption can break Concentration in Baldur’s Gate 3. There’s a Consitution check that brings this to the forefront. Passing that check makes it so you can keep the spell effect up. That means it’s a good idea to check which spells use this before setting them in your memorized spells. You can only concentrate on 1 concentration spell at a time.
Spells/abilities that require Concentration will only stay active as long as the caster stays focused on maintaining the effect. The concentration can be broken by taking damage or some other effects. There are even certain spells and status effects that can break concentration. You can’t well cast a spell while you’re running around on fire.
To see if a spell requires Concentration to use, just hover your cursor over the spell in question. If it does indeed need all of your spellcaster’s focus, “Concentration: Required” will appear in the UI element. Once the spell is cast, look on the UI in-game and you will see a glowing outline on it. The outline will denote a spell that has concentration. If you lost concentration, the outline will disappear and the spell effect will end.
It might also help to know what you need rests to restore spell slots, as well as figuring out how to swap spells in and out. You might also want to take a gander at some of our other guides for the game. If you need a primer on other combat basics in Baldur’s Gate 3, you can find that. We also talked through how death works if you’re running into it a lot.