A Saving Throw, also called a save (and depending on the ability it's tied to, Strength Save, Dexterity Save, etc.), is a die roll the game makes for a creature to decide whether it can avoid or reduce the harmful effects of various threats, such as a spell, poison, trap, and so on. The creature's Ability Score Modifier and Proficiency Bonus (if proficient in that type of saving throw) are added to the roll.
Result = D20 + Ability Score Modifier + Proficiency Bonus (if proficient)
Each Saving Throw is tied to an Ability Score that determines its type. Accordingly, it can be referred to as a Strength Save, Dexterity Save, Constitution Save, and so on. For a save to succeed, it must reach or exceed a value known as the Difficulty Class (DC).
Saving Throws are affected by the Ability Score Modifier of the ability they're tied to. In addition to that, a creature can be proficient in a type of Saving Throw, allowing it to add its Proficiency Bonus to the roll.
Saving Throws can also be affected by Advantage or Disadvantage. For example, Elves have Advantage on Saving Throws against being Charmed. As another example, the Bleeding condition incurs Disadvantage on Constitution Saves.
Main page: Ability Score Modifier
Following is the Ability Score Modifier table based on the value of the Ability Score being used for the save:
Following is the table of Proficiency Bonus values, by Level of the creature making the save:
|1 to 4
|5 to 8
|9 to 12
If a creature casts a spell that forces another to make a save, the DC is determined according to the properties of the spell caster, using the following formula:
Difficulty Class = 8 + Ability Score Modifier + Proficiency Bonus
In Baldur's Gate 3, the same ability modifiers apply when casting a spell from a Scroll, even when the spell being cast is not normally available to your class. For instance, a Cleric casting Shatter (a spell not normally available to Clerics) from a scroll adds its Wisdom modifier to the Saving Throw DC.
The Proficiency needed to gain the Proficiency Bonus is spellcasting. All creatures capable of casting spells through their Class, Subclass, or Feats have this proficiency. If a creature that can't normally cast spells uses a scroll or other item to cast one, it will also receive its Proficiency Bonus on the Attack Roll or Saving Throw DC of that spell.
In the case of threats that don't originate from a spell caster, such as a trap or a poisonous apple, the game sets the DC based on how serious the threat is supposed to be. For example, a rather ineffective trap could have a DC of just 5, whereas a very powerful one could have a DC of 15. A slightly spoiled tart could impose a Constitution Save of DC 5, whereas a potent venom from a snake could impose a DC 15 Constitution Save on the hapless victim.
Making a successful Saving Throw could mean avoiding negative effects entirely, or it could merely mean reducing the damage taken, usually by half. Depending on the threat, there could also be other rules that determine what happens on a failed or successful save.