Advantage and Disadvantage Rules
Advantage and Disadvantage are the core dice-rolling modifiers in Dungeons & Dragons 5th Edition, replacing the layered situational bonuses of earlier editions with a single, elegant mechanic. This page covers how the system works, the scenarios that trigger it, and the stacking rules that trip up even experienced Dungeon Masters. Getting these boundaries right matters — a misapplied Advantage can swing a combat encounter in ways the rules never intended.
Definition and scope
Roll two d20s instead of one. That is the entire mechanical heart of Advantage. When a creature has Advantage on a roll, it rolls 2d20 and takes the higher result. When it has Disadvantage, it rolls 2d20 and takes the lower result. The rule appears in the Player's Handbook (Chapter 7) and applies to attack rolls, ability checks, and saving throws — the three categories of d20 rolls in the game.
What it does not apply to is damage. Advantage never doubles damage dice, and it has no interaction with how specific combat mechanics work beyond the initial attack roll. That boundary is worth keeping sharp.
The probability shift is real and measurable. A straight d20 roll produces any result from 1 to 20 with equal 5% probability each. Rolling with Advantage raises the effective average result from 10.5 to approximately 13.8. Rolling with Disadvantage drops it to roughly 7.2. That spread — nearly 7 points between the two states — explains why the mechanic carries so much weight at the table.
How it works
The procedure has three steps:
- Identify the roll type. Confirm the roll is an attack roll, ability check, or saving throw. Other rolls (damage, death saves under certain conditions, percentile checks) follow their own rules.
- Determine the condition. One or more sources grant Advantage, Disadvantage, or both.
- Apply the result. Take the higher die (Advantage) or the lower die (Disadvantage), then apply all flat modifiers — proficiency bonus, ability modifier, magic item bonuses — to that single die result as normal.
The modifiers always apply after the dice selection, not to both dice. A rogue with a +5 modifier who rolls 14 and 9 with Advantage uses 14 + 5 = 19. The 9 is discarded entirely.
Death saving throws interact with the system in a specific way: rolling a natural 1 on a death save counts as 2 failures, and rolling a natural 20 restores the character to 1 hit point. Advantage and Disadvantage still apply to death saves where specified, but the natural 1 and natural 20 thresholds are evaluated against the actual die face — not the final total. This is one of the more precise rulings clarified in the D&D FAQ.
Common scenarios
The Player's Handbook and Dungeon Master's Guide list explicit Advantage triggers. Among the most frequently encountered:
- Prone targets. Melee attacks against a prone creature have Advantage; ranged attacks against a prone creature have Disadvantage.
- Unseen attackers. Attacking a target the attacker cannot see imposes Disadvantage; being attacked by an unseen attacker means the defender does not benefit from any AC-boosting reaction (the attacker still rolls, just with Disadvantage if the defender's location is unknown).
- Restrained condition. Attack rolls against a restrained creature have Advantage; the creature's own attack rolls have Disadvantage.
- Paralyzed condition. Attack rolls against a paralyzed creature have Advantage, and any attack that hits while the creature is within 5 feet is automatically a critical hit.
- The Help action. One creature uses its action to help an ally, granting that ally Advantage on the next ability check or attack roll against a specific target before the start of the helper's next turn.
- The Reckless Attack feature. Barbarians can choose Advantage on melee weapon attack rolls using Strength during their first attack on a turn — but all attack rolls against them have Advantage until their next turn.
This is the mechanic's elegance on display: a single binary state captures the tactical texture of flanking, exhaustion, superior positioning, and magical compulsion without a separate modifier for each.
Decision boundaries
The rule that generates the most table debate: multiple sources of Advantage do not stack. If 3 separate effects grant Advantage on the same roll, the character still rolls 2d20 and takes the higher — not 3d20, not 4d20. This is explicit in Player's Handbook Chapter 7: "If multiple situations affect a roll and each one grants advantage or imposes disadvantage on it, you don't roll more than one additional d20."
The cancellation rule is equally clean. If a character has Advantage and Disadvantage on the same roll — from any number of sources on either side — the two cancel out and the player rolls a single d20. Three sources of Advantage and one source of Disadvantage still produces a straight roll. This is where the system parts ways with older editions' modifier arithmetic, and it is a deliberate design choice rather than an oversight. For a broader look at where this mechanic fits within the game's structure, see key dimensions and scopes of D&D.
Advantage vs. flat bonuses: the comparison worth making. The Lucky feat (Player's Handbook, p. 167) allows a player to spend a luck point to roll an additional d20 and choose which result to use — even after seeing the roll. This interacts with Advantage and Disadvantage in a specific way: if the character has Disadvantage and uses Luck, they roll 3 dice and the player chooses which die the character uses, while the DM chooses which die any other relevant party uses. The mechanic is functionally different from Advantage stacking and remains one of the more nuanced rulings at the intersection of feats and the core system.
Flat bonuses from spells like Bless (+1d4 to attack rolls and saving throws) or the Bardic Inspiration die do stack with Advantage — because they modify the result after the die is selected, not the dice count itself. Advantage changes which die counts. Bless changes what gets added to it. The two operate in different layers of the same calculation.