Home/Rules/Core Mechanics/Advantage & Disadvantage

Advantage & Disadvantage

Advantage and disadvantage are the core mechanics that modify dice rolls in D&D 5e. Roll twice, take the higher (advantage) or lower (disadvantage) result.

How Advantage and Disadvantage Work

When you have advantage, roll two d20s and use the higher result. When you have disadvantage, roll two d20s and use the lower result.

Key Rules:

  • Applies to attack rolls, ability checks, and saving throws
  • Multiple sources of advantage don't stack (you still only roll twice)
  • Multiple sources of disadvantage don't stack
  • If you have both advantage AND disadvantage, they cancel out - roll normally with one d20

The Cancellation Rule:

  • Even if you have 3 sources of advantage and 1 of disadvantage, they ALL cancel
  • You roll a single d20 as normal
  • This is intentional to keep the system simple

Common Sources of Advantage

Attack Rolls with Advantage:

Ability Checks with Advantage:

Saving Throws with Advantage:

  • Gnome's Gnome Cunning (vs. magic)
  • Halfling's Brave (vs. frightened)
  • Various class features and spells

Common Sources of Disadvantage

Attack Rolls with Disadvantage:

  • Attacking a prone target from more than 5 feet away
  • Attacking when blinded
  • Attacking when poisoned
  • Attacking when restrained
  • Ranged attacks at long range
  • Ranged attacks within 5 feet of a hostile creature
  • Using a weapon you're not proficient with
  • Wearing armor you're not proficient with

Ability Checks with Disadvantage:

  • Exhaustion level 1
  • Heavy obscurement (Perception)
  • DM-imposed circumstances

Saving Throws with Disadvantage:

The Math Behind Advantage

Statistical Impact:

  • Advantage is roughly equivalent to +5 on average
  • Disadvantage is roughly equivalent to -5 on average
  • The actual bonus varies based on the target number

Critical Hit Probability:

  • Normal roll: 5% chance of natural 20
  • With advantage: ~9.75% chance of natural 20
  • With disadvantage: ~0.25% chance of natural 20

Why This Matters:

  • Advantage is extremely powerful for crit-fishing builds
  • Disadvantage makes critical hits very rare
  • Rogues especially benefit from advantage (Sneak Attack)

Common Mistakes

Common Mistake
Thinking multiple sources of advantage stack
Common Mistake
Forgetting that any disadvantage cancels all advantage
Common Mistake
Not knowing ranged attacks within 5 feet have disadvantage
Common Mistake
Forgetting that wearing non-proficient armor causes disadvantage on ALL attacks

DM Tips

DM Tip
Use advantage/disadvantage instead of small +/- modifiers
DM Tip
Grant advantage for creative player actions
DM Tip
Remember that advantage cancels disadvantage completely
DM Tip
Advantage is roughly +5 - use that for mental math