DnD Action Types: Action, Bonus Action, and Reaction
The action economy in Dungeons & Dragons 5th Edition governs what a creature can accomplish on its turn, structuring every round of combat into discrete categories of activity. Three primary action types — the action, the bonus action, and the reaction — each carry distinct rules for when they trigger, what abilities they enable, and how they interact with one another. Understanding how these categories are defined and constrained is essential for running combat accurately, whether at the table or in organized play formats like the D&D Adventurers League.
Definition and scope
The D&D Basic Rules, published free by Wizards of the Coast, define three action types available to most creatures during combat, alongside movement:
- Action: The primary activity of a turn. A creature gets exactly 1 action per turn. Actions include attacking, casting a spell with an action casting time, using an item, taking the Dash or Dodge action, and more.
- Bonus Action: A supplemental activity that certain features, spells, or class abilities grant. A creature gets at most 1 bonus action per turn, but only if a specific rule or ability explicitly says it grants one. Bonus actions cannot be freely declared — the trigger must exist.
- Reaction: A single response to a specific trigger, usable once per round (not per turn). A creature regains its reaction at the start of its own turn. Reactions can occur on another creature's turn.
These three types operate independently. Having a bonus action does not consume an action, and using a reaction on another creature's turn does not subtract from action economy on the reacting creature's next turn.
For broader context on how these rules sit within the full turn structure, the how DnD works conceptual overview covers the round-by-turn sequence in detail.
How it works
Each combat round is 6 seconds of in-game time. Within a round, each participant takes one turn determined by initiative order.
On a creature's turn, it may:
- Move up to its full speed (before, after, or between other activities).
- Take 1 action.
- Take 1 bonus action, if a currently available ability grants one.
- Interact freely with 1 object as part of movement or action (e.g., drawing a weapon).
Between turns, a creature may:
- Take 1 reaction, if a trigger occurs and a feature grants one.
Key structural constraint: bonus actions require an explicit grant. A Fighter cannot declare a bonus action attack simply because no other bonus action was used. By contrast, the dnd-opportunity-attacks-rules page details the most common example of a reaction — the opportunity attack — which triggers automatically when a hostile creature within reach moves out of reach without Disengaging.
A critical mechanical separator is casting time. Spells with a casting time of "1 action" consume the action. Spells with a casting time of "1 bonus action" consume the bonus action. The dnd-spellcasting-rules page addresses the additional constraint that when a bonus action spell is cast, the only spells castable with the action on that same turn are cantrips.
Common scenarios
Rogue Cunning Action: Rogues gain Cunning Action at level 2, granting a bonus action usable each turn to Dash, Disengage, or Hide. This is one of the most direct examples of a class feature conferring a reliable bonus action economy every turn.
Shield Spell (Reaction): The Shield spell (found in the Player's Handbook) has a casting time of 1 reaction and triggers when hit by an attack or targeted by the Magic Missile spell. The reacting creature gains +5 AC until the start of its next turn. This exemplifies a reaction with a specific trigger and spell slot cost.
Two-Weapon Fighting: When a creature takes the Attack action with a light melee weapon, it may use a bonus action to make a single attack with a different light melee weapon held in the other hand. No ability score modifier is added to the bonus attack's damage by default. This scenario is covered in depth in the dnd-weapons-rules section.
Bardic Inspiration: Bards can use a bonus action to give another creature an Inspiration die, which that creature then uses as a reaction-adjacent resource — though the die itself is not a reaction, its expenditure by the recipient is governed by specific trigger conditions.
Counterspell (Reaction): Counterspell triggers when a creature within 60 feet begins casting a spell, and is cast as a reaction. This creates an interaction between two creatures' action economies across turns — a defining feature of reaction-type mechanics.
Decision boundaries
Action vs. Bonus Action
These are not interchangeable. A feature that grants a bonus action attack cannot be used as an action, and vice versa. A creature cannot "save up" bonus actions across turns. If the bonus action is not used, it is lost at the end of the turn.
Reaction timing precision
A reaction occurs at a specific interrupt point. The Shield spell, for example, can be cast after an attack roll succeeds but before damage is applied — because it raises AC retroactively. This interrupt window is explicitly defined in the spell description, not a general rule of reactions. The dnd-saving-throws-rules page addresses comparable interrupt mechanics in saves.
Stacking bonus actions
No mechanic in the core rules permits 2 bonus actions in a single turn. Features that might appear to grant a second bonus action (e.g., a Haste spell's additional action, which is its own restricted action type) are deliberately distinguished. The Haste spell grants an additional action usable only for the Attack action (1 attack only), Dash, Disengage, Hide, or Use an Object — and is not a bonus action.
Reactions across rounds
A creature that uses its reaction on another creature's turn does not carry any deficit into its next turn. All action resources — 1 action, 1 bonus action (if applicable), 1 reaction, and movement — reset at the start of each new turn. This is consistent with how the dnd-combat-rules framework defines the round boundary.
For a full index of rules pages organized by topic, the site index provides a structured reference across all major rules categories.
References
- D&D Basic Rules — Wizards of the Coast / D&D Beyond
- Player's Handbook — Wizards of the Coast
- D&D Adventurers League — Organized Play Documentation
- D&D Beyond Rules Glossary — Official Digital Reference