Are you looking to calculate spell save DC for D&D 5e?

A spell's difficulty class (DC) is the target number that a creature must meet or exceed with a saving throw in order to resist the effects of a spell. The spell save DC is determined by the spellcaster's proficiency bonus, spellcasting ability score modifier, and any additional bonuses from feats, items, or other sources.

The formula to calculate it is simple:

• 8 + spellcasting ability modifier + proficiency bonus = spell save DC.

For NPCs and monsters, you can determine their proficiency bonus using their Challenge Rating (CR) as their level. So a creature with a CR of 8 would have a +3 proficiency bonus, just like a Level 8 character would.

For example, if you're a level 5 Wizard with 18 intelligence, this is how you'd calculate your spell saves.

Step 1: Determine the Spellcasting Ability Modifier

The first step in calculating a spell save DC is to determine the spellcasting ability modifier.

Each class in 5e has a specific spellcasting ability associated with it, and that is what determines which ability score is used to calculate the spell save DC. The chart below shows all of the 5e classes with the spellcasting trait and the associated ability score.

For example, if you are a wizard, your spellcasting ability is Intelligence, so you would use your Intelligence modifier to calculate your Spell DC. If you are a cleric, your spellcasting ability is Wisdom, so you would use your Wisdom modifier instead.

Step 2: Determine the Proficiency Bonus

The next step is to determine the character's proficiency bonus. The bonus scales with character level and represents their overall skill growth and experience.

You will start at +2 as a 1st-level character and increases as you gain levels. Remember, to calculate NPC and monster proficiency, you use their CR instead of a level. The chart below shows which levels the proficiency bonus increases.

Step 3: Add the Spellcasting Ability Modifier and Proficiency Bonus

Once you have determined the spellcasting ability modifier and proficiency bonus, you add them together to get the spell save DC. The formula is:

• Spell DC = 8 + proficiency bonus + spellcasting ability modifier

For example, let's say you are a 5th-level wizard with an Intelligence score of 18 (+4 modifier). Your proficiency bonus at 5th level is +3. You would calculate your spell save DC like this:

• 8 (base) + 3 (proficiency) + 4 (spellcasting ability modifier) = 15 spell DC

In this case, your DC would be 15.

Step 4: Check for Additional Bonuses

Finally, be sure to check for any additional bonuses that might apply, such as those from feats, magic items, or other sources. For example, the Ioun Stone of Mastery increases your proficiency bonus by 1, which increases your spell DC. So be sure to add that into the equation, too.

And some items like the Staff of Power add to the spell save directly. Make sure not to miss anything like that, especially if you're not using a tool like D&D Beyond that automatically calculates things.

Conclusion

Wrapping up, calculating your spell DC in D&D 5e is easy: just determine your spellcasting ability modifier and proficiency bonus, and then add them to the base save of 8. Remember, 8 + proficiency bonus + spellcasting ability modifier = spell save DC.

That's all there is to it!

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