Disadvantage is a mechanic in Baldur's Gate 3. While players are under the effect of Disadvantage and perform an ability check, saving throw or an attack roll they will roll a second D20 while making that role and use the lower of those rolls to decide the outcome.
Disadvantage in Baldur's Gate 3
Sometimes a special ability or spell tells you that you have disadvantage on an ability check, a saving throw, or an attack roll. When that happens, you roll a second D20 when you make the roll. The game will use the lower of the two rolls to decide the outcome. For example, if you roll a 17 and a 5, the game will use the 5 to decide the outcome of the roll and the 17 will be discarded.
Disadvantage is one of the worst situations you can be on when rolling on Baldur's Gate 3 and on any D&D game, as it halves your chance of success and should be avoided in all situations.
A Saving Throw can be modified by a situational bonus or penalty and can be affected by advantage and disadvantage.
Disadvantage and Advantage
Advantage and disadvantage are applied to the roll of the D20. Advantage means that you roll the d20 two times when making an Attack Roll, Ability Check or Saving Throw, and use the higher of the two values. On the other hand, disadvantage means that you roll the d20 two times but in this case, use the lower of the two values.
Disadvantage is one of the worst situations you can be on when rolling on D&D, and should be avoided at all costs. While advantage nearly doubles your chance of success and should be sought out.
How to Acquire Disadvantage
You usually gain Disadvantage by being on lower ground than your opponent or by the use of special abilities, Actions, or Spells.
Disadvantage and Advantage Interactions
If multiple situations affect a roll and each one grants Advantage or imposes Disadvantage on it, you don’t roll more than one additional D20. If two favorable situations grant advantage, for example, you still roll only one additional d20.
If circumstances cause a roll to have both Advantage and Disadvantage, you are considered to have neither of them, and you roll one D20. This is true even if multiple circumstances impose disadvantage and only one grants advantage or vice versa. In such a situation, you have neither advantage nor disadvantage.