D&D Skill Check Success Chance Calculator

Calculate your chance to pass a D&D skill check. Enter the DC, ability modifier, proficiency or expertise, and advantage or disadvantage to see the roll needed, success chance, passive score, and optional d20 result.

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Skill Settings

Result

Success Chance -
Roll Needed -
Total Modifier -
Passive Score -
Roll Type -

Enter a DC and modifiers to see your success chance. Roll a d20 when you want an actual check result.

Skill check odds

The calculator shows your chance to meet or beat the DC before you roll. In D&D 5e, natural 1 and natural 20 are not automatic failure or success on skill checks unless your table uses that house rule.

Recent Checks

Handy for multiple attempts or contested checks—stores up to eight rolls.

No rolls yet.

Rolling something other than a skill check?

Skill checks are different from saves and initiative. Use the D&D saving throw roller for spell saves, the initiative tracker for turn order, or the ability score generator when building a character.

How Skill Checks Work

A skill check is a d20 roll plus the relevant ability modifier, proficiency if it applies, expertise if you have it, and any situational bonus or penalty. Compare the total against the Difficulty Class (DC).

Core formula

d20 + skill modifier vs DC
  • DC is the target number set by the DM (higher DC = harder task).
  • Modifier usually comes from an ability modifier plus proficiency bonus if proficient.
  • Expertise doubles the proficiency bonus for that skill.

Advantage & disadvantage

  • Advantage: roll 2d20 and take the higher result.
  • Disadvantage: roll 2d20 and take the lower result.

Common examples

  • Perception: spot a hidden lever, trap, or enemy movement in a noisy room.
  • Stealth vs passive Perception: sneak past a guard — your roll is compared to the guard’s passive score.
  • Athletics / Acrobatics: jump a gap, climb quickly, resist being shoved, or escape a grapple.

Success chance and passive checks

  • Higher modifiers improve the chance to meet the DC; advantage improves the odds by keeping the better d20.
  • Passive checks use 10 + modifiers and are useful for repeated or hidden checks like Perception.
  • A natural 20 is not normally an automatic success on skill checks, though some tables use that house rule.

How to Use the Skill Check Calculator

  1. Choose a skill such as Acrobatics, Investigation, or Stealth. The calculator automatically displays which ability modifier the skill uses.
  2. Enter your ability modifier, proficiency bonus, and any extra bonuses (guidance, magic items, etc.).
  3. Select whether you are proficient or have expertise, and decide if the roll uses advantage or disadvantage.
  4. Press Roll Skill Check or tap the space bar to roll a d20, add modifiers, and see if you meet the DC.
  5. Optional: calculate passive skill (10 + modifiers) to compare against traps or hidden creatures.

What This Skill Check Calculator Handles

  • All 18 skills: Acrobatics through Survival with automatic ability references.
  • Proficiency/Expertise toggles: Adds proficiency or doubles it for rogues/bards.
  • Advantage/Disadvantage: Roll two d20s and keep the higher/lower automatically.
  • DC comparison: The summary displays success/failure instantly.
  • History + passive scores: View recent rolls and passive skill values for exploration scenes.

Examples and Tips

Example: a rogue with Dexterity +5, proficiency bonus +4, and expertise in Stealth rolls with a +13 modifier plus any situational bonuses. Set the DC, choose advantage if conditions help the rogue, and compare the total to the DM's target number. Use passive scores for repeated situations like keeping watch, and keep the history panel open for contested checks.