HOW DO I determine if my rogue and fighter have proficiency in spellcasting/scrollcasting?

[MythTrip]

Do they always have proficiency in casting their cantrips?

Also how do I determine if they have proficientcy in casting scrolls?

[Sencho]

Damaging cantrips scale with the casting stat associated with class or feat giving you access to the cantrip (Int, Wis, Cha)

Scrolls always use the modifier of the current class, even for non-spellcasters: Fighter and Rogue use Intelligence, Monk uses Wisdom, and Barbarian uses Charisma.

Your current class refers to whichever class you have picked on the last level up. If you put 11 levels into Cleric, and then 1 level into Fighter, then all subsequent scrolls will be cast using Intelligence (because your current class is considered to be Fighter).

[Wuorg]

In BG3, everyone can use scrolls without restriction, barring general spellcasting restrictions like Rage and Silence. Scrolls will always benefit from Proficiency Bonus, as will any spells the character knows through normal means. Keep an eye on which ability score the spell uses for rolls, as this can change depending on the source.

[Detective Costeau]

Worth noting a lot of martial classes won't really have the stats to use offensive spells effectively from scrolls- unless you've invested a lot more than usual in mental attributes the attack rolls won't be very accurate and the save DCs will be pretty low.

However, buffs like Haste and Bless don't require attack rolls or saves, so those are still extremely useful for anyone.

[MythTrip]

Ok so spellcasting always uses your general proficiency? So if my proficiency is +2 due to char level, I always add +2 to scroll casting + the appropriate ability stat (ie, 16 intelligence = +3) ? I thought scroll casting was like weapons: With weapons you have to be proficient in longswords to get the +2 bonus wielding a longsword.

[Detective Costeau]

I think the game just treats everyone as being 'proficient' with scrolls.

[Wuorg]

Originally posted by MythTrip:

Ok so spellcasting always uses your general proficiency? So if my proficiency is +2 due to char level, I always add +2 to scroll casting + the appropriate ability stat (ie, 16 intelligence = +3) ? I thought scroll casting was like weapons: With weapons you have to be proficient in longswords to get the +2 bonus wielding a longsword.

Yup, everyone is "proficient" with scrolls in BG3. In 5e there are class-based restrictions on who can use scrolls (with a couple exceptions), but not in BG3.