Bonus actions are easily one of the most confusing parts of a combat turn in 5th Edition. In fact, designer Mike Mearls dislikes bonus actions and has declared that they are “fairly hacky” and that he prefers to run games without them. So why do bonus actions exist, and how can we understand them? To answer the first question, let’s take a look at the genealogy of bonus actions.

In the 3rd Edition era, the concept of swift actions was not part of the core books but was introduced in the Miniatures Handbook shortly after the release of the core game. The SRD (System Reference Document) for 3.5 states:

A swift action consumes a very small amount of time, but represents a larger expenditure of effort and energy than a free action. You can perform one swift action per turn without affecting your ability to perform other actions. […] You can perform only a single swift action per turn, regardless of what other actions you take. [However, many characters] never have an opportunity to take a swift action.

Basically, a swift action is a once-per-turn chance to do something that is (usually) less powerful than a standard action. It also offers the opportunity for same-turn combos: a Shadow Hand swordsage could use Cloak of Deception (a swift action) to become invisible for the turn and then attack with a bonus as a standard action. However, note that a character without any swift action abilities can’t use a swift action.

In 4th Edition, minor actions were part of the core rules. Minor actions were similar to swift actions in that they were a once-per-turn option for a smaller power, such as sustaining an effect (keeping a power active) or casting certain spells. They could be prepared using the ready an action option or gained by spending an action point. Minor actions were a key part of the 4th Edition ruleset, but they also contributed to the infamously long and complicated nature of fourth edition combat.

That brings us to 5th Edition, which includes bonus actions in the core rules:

Various class features, spells, and other abilities let you take an additional action on your turn called a bonus action. The Cunning Action feature, for example, allows a rogue to take a bonus action. You can take a bonus action only when a special ability, spell, or other feature of the game states that you can do something as a bonus action. You otherwise don’t have a bonus action to take.
      You can take only one bonus action on your turn, so you must choose which bonus action to use when you have more than one available.
      You choose when to take a bonus action during your turn, unless the bonus action’s timing is specified, and anything that deprives you of your ability to take actions also prevents you from taking a bonus action.

In 5th Edition, bonus actions continue to be a once-a-turn option to do something in addition to using your action to attack, cast a spell, disengage, etc. A key point to note is that you don’t necessarily have a bonus action on your turn unless you have a specific ability, spell, or feature to use as a bonus action. So by the rules as written, you can’t make an ability check, draw a second weapon, or kick an enemy as a bonus action, though your GM may decide to rule otherwise.

That doesn’t seem too difficult, but the confusion often arises when considering two-weapon fighting. The rules for two-weapon fighting are worth reading (and rereading and rereading to internalize the exact wording):

When you take the Attack action and attack with a light melee weapon that you’re holding in one hand, you can use a bonus action to attack with a different light melee weapon that you’re holding in the other hand. You don’t add your ability modifier to the damage of the bonus attack, unless that modifier is negative.

So you can attack with two light melee weapons using the Attack action and a bonus action. Note that an unarmed strike is not a weapon (it doesn’t appear in the Weapons table of the updated Player’s Handbook), but you can make a melee weapon attack with an unarmed strike. Thus, by the strict interpretation of the rules as written, you can’t use two-weapon fighting with unarmed strikes. Of course, this doesn’t really make sense—if you can attack with two daggers, why not with two fists?—so most games I’ve seen interpret this more generously. But now we start to see why bonus actions can get a little messy when combined with two-weapon fighting.

For GMs (and designers), it’s worth noting that most monsters don’t have bonus actions, which makes running them much simpler. Even monsters based off of humanoid characters, such as the bandit captain, typically have any bonus action attacks rolled into a Multiattack feature.

Let’s also cover some common questions for players surrounding bonus actions:

• If a fighter with Action Surge wielding two shortswords takes the Attack action and a bonus action to attack and uses Action Surge to attack again, they get three attacks total (Attack action + bonus action + Attack action). If they have the Extra Attack feature, they can make five attacks total (Attack action for two attacks + bonus action + Attack action for two attacks).
• Similarly, if a monk takes the Attack action and then uses Flurry of Blows, they also get three attacks total (Attack action + bonus action to make two unarmed strikes). If they have the Extra Attack feature, they can make four attacks total (Attack action for two attacks + bonus action to make two unarmed strikes).

If you’re still confused, don’t worry—you’re not alone. What’s important is that everyone at your table has fun playing the game. And if you’re bothered by someone else using a different interpretation of the rules, talk to the GM outside of a game session to address it, rather than stopping in the middle of combat to discuss rules.

Leave a comment below if you have questions or want to suggest future topics for the Mastering the Mechanics series!

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