Spell DC
Source Player Core pg. 395
Many times, instead of requiring you to make a spell attack roll, the spells you cast require those within the area or targeted by the spell to attempt a saving throw against your spell DC to determine how the spell affects them. Calculate it using the following formula.
Spell DC = 10 + spellcasting attribute modifier + proficiency bonus + other bonuses + penalties
Spell DC = 10 + spellcasting attribute modifier + proficiency bonus + other bonuses + penalties