D&D 5e Spell Save DC & Spell Attack Calculator
Choose your class, level and spellcasting ability score to get your spell save DC and spell attack bonus. Then see how likely a creature is to fail its saving throw, or how often your spell attacks will hit.
Your spellcasting
Against a target
| Save bonus | Fails | Fails (advantage) |
|---|
Spell save DC formula
When you cast a spell that forces a creature to make a saving throw, the creature has to equal or beat your spell save DC. When a spell asks you to make a spell attack, you roll a d20 and add your spell attack bonus. Both use the same two numbers: your proficiency bonus and your spellcasting ability modifier.
Spell attack bonus = proficiency bonus + spellcasting ability modifier
The formulas are identical in the 2014 and 2024 rules. Magic items and some class features can add a further bonus to one or both.
Spellcasting ability by class
| Class | Spellcasting ability | Caster type |
|---|---|---|
| Bard | Charisma | Full caster |
| Cleric | Wisdom | Full caster |
| Druid | Wisdom | Full caster |
| Paladin | Charisma | Half caster |
| Ranger | Wisdom | Half caster |
| Sorcerer | Charisma | Full caster |
| Warlock | Charisma | Pact magic |
| Wizard | Intelligence | Full caster |
Subclasses that add spellcasting to non-caster classes usually use Intelligence. Choose Other in the calculator and pick the ability yourself.
Spell save DC by level
Your proficiency bonus rises at levels 5, 9, 13 and 17. The table shows the DC for different spellcasting ability scores, before any item bonuses.
| Level | Proficiency | Score 14 (+2) | Score 16 (+3) | Score 18 (+4) | Score 20 (+5) |
|---|---|---|---|---|---|
| 1–4 | +2 | 12 | 13 | 14 | 15 |
| 5–8 | +3 | 13 | 14 | 15 | 16 |
| 9–12 | +4 | 14 | 15 | 16 | 17 |
| 13–16 | +5 | 15 | 16 | 17 | 18 |
| 17–20 | +6 | 16 | 17 | 18 | 19 |
A typical caster who starts with 16 in their main ability and raises it to 20 by level 8 has DC 13 at level 1, DC 14 at level 4, DC 16 at level 8 and DC 19 at level 17.
How likely is a creature to fail its save?
A creature succeeds if its d20 roll plus its saving throw bonus equals or beats your DC. Unlike attack rolls, a natural 20 does not automatically succeed and a natural 1 does not automatically fail on a saving throw, under both the 2014 and 2024 rules.
Against DC 15, a creature with a +2 bonus needs a 13 or higher and fails 60% of the time. Creatures with Magic Resistance roll with advantage, which turns that 40% success chance into 64%. That is why save-or-suck spells are best aimed at a creature's weakest saving throw: big monsters often have strong Strength and Constitution saves but weak Intelligence, Wisdom or Charisma.
Spell attacks vs saving throw spells
Spell attacks use your spell attack bonus against the target's Armor Class, so they can score critical hits and benefit from advantage. Saving throw spells use your DC against the target's saving throw bonus; they cannot crit, but many still deal half damage when the target succeeds. Use the DPR calculator to compare a spell attack cantrip with a weapon attack.
Tip: Raising your spellcasting ability from 18 to 20 adds +1 to your DC, which is worth 5 percentage points on every save a creature makes against you.