Can you use a readied action to act on a different round?

Question

From the PHB, page 193:

Sometimes you want to get the jump on a foe or wait for a particular circumstance before you act. To do so, you can take the Ready action on your turn so that you can act later in the round using your reaction.

And page 189:

A round represents about 6 seconds in the game world. During a round, each participant in a battle takes a turn. The order of turns is determined at the beginning of a combat encounter, when everyone rolls initiative. Once everyone has taken a turn, the fight continues to the next round if neither side has defeated the other.

Emphasis mine.

Taken together, these seem to imply that, by RAW, when you ready an action, you can only use that action before the end of the round. Once the last combatant in the initiative order finishes their turn and the next round begins, if you haven't used your reaction yet, then you're out of luck.

This essentially means that, if you are last or close to last in initiative order, you are effectively barred from using readied actions for that entire combat. This can create some strange situations.

For example, I recently had the following happen: Our party took some goblins by surprise. Only one member (the scout) was close enough to attack them, so the rest of us chose to stay back and instead ready actions to attack at range as soon as our scout flushed out the enemy. Combat begins, initiative is rolled, and we take our surprise round. The scout moves forwards and attacks one goblin, while the rest of us use ready actions.

On the next round, the goblins, seeing that they are outnumbered, begin to flee. One of them runs for help, and my two allies use their reaction to attack, but when I try to attack as well, I'm told by the DM that I can't.

Why? Well, because I rolled a low initiative. My two allies rolled high, and thus were able to act before the goblins moved, readying their actions during the first round of combat. I, on the other hand, hadn't yet acted during that round, and since the round had ended between my first ready action (during the surprise round) and now, it was no longer valid.

So, my questions are twofold. First, is this how the rules actually work as written? Are my DM and I reading this correctly? Or is there a passage somewhere else that we're missing?

Second, assuming the answer to #1 is yes, would it break anything to allow readied actions to persist until the beginning of your next turn, rather than the end of the current round? How so?

Answer 1

There are 2 definitions of "round" in 5e. There is the definition of "round" that you quote, which is from initiative position intMax to initiative position 0 (or negative if you manage that some how).

Then there is the definition used here for readied actions. This is the same definition used in "once per round" effects such as certain powers. This definition begins at the beginning of your turn and ends at the beginning of your next turn.

Because (unlike in 4e), readying an action and activating it, doesn't move your initiative order position, and because it matches the readied action refresh timer (which happens to use the same 1/round definition of round), readied actions can be used at any point in either the current round or the next round prior to your turn.

Here's how reactions refresh:

When you take a reaction, you can’t take another one until the start of your next turn. If the reaction interrupts another creature’s turn, that creature can continue its turn right after the reaction. (Player's Basic p70)

This is a large part of the support that leads me (and many others) to believe that readied actions can roll up to your next turn.

Answer 2

This was a bug in the PHB wording of the rules. From Player's Handbook Errata:

Ready (p. 193). You have until the start of your next turn to use a readied action.

(Thanks to Can you forgo your readied action to take an opportunity attack instead? for highlighting it.)

Answer 3

The rules use round more than one way. The ruling was incorrect.

Most actions are clearer about how long they last, relative to your turn (basic rules, p. 72).

Disengage: If you take the Disengage action, your movement doesn’t provoke opportunity attacks for the rest of the turn.

Dodge: When you take the Dodge action, you focus entirely on avoiding attacks. Until the start of your next turn, any attack roll made against you has disadvantage. . . .

Help: . . . When you take the Help action, the creature you aid gains advantage on the next ability check it makes to perform the task you are helping with, provided that it makes the check before the start of your next turn.

Only the Ready rules mention rounds, and it’s not entirely consistent with the descriptions of rounds (p. 69) and reactions (p. 70) in the “Combat” chapter.

Ready: Sometimes you want to get the jump on a foe or wait for a particular circumstance before you act. To do so, you can take the Ready action on your turn so that you can act later in the round using your reaction. . . . When the trigger occurs, you can either take your reaction right after the trigger finishes or ignore the trigger. Remember that you can take only one reaction per round.

A round represents about 6 seconds in the game world. During a round, each participant in a battle takes a turn. The order of turns is determined at the beginning of a combat encounter, when everyone rolls initiative. Once everyone has taken a turn, the fight continues to the next round if neither side has defeated the other.

Reactions: . . . When you take a reaction, you can’t take another one until the start of your next turn.

The actual definition of reactions isn’t “one per round,” it’s “not until the start of your next turn.” The two statements aren’t equivalent if you count rounds from the start of combat, the way “The Order of Combat” describes it. (For example, you can make an opportunity attack immediately before your turn and again immediately after it, in the same “round.”) Thus, the ruling in play leads to a contradiction – it was incorrect.

However, the rules are consistent if you read round as the duration between your own turns, which is exactly the amount of time until you can take another reaction.

Ready: Sometimes you want to get the jump on a foe or wait for a particular circumstance before you act. To do so, you can take the Ready action on your turn so that you can act later in the round [until your next turn] using your reaction.

You could also read “you can act later in the round” descriptively (something you can do) rather than prescriptively (this is the only way you can do it). Usually, the rules use may for the latter, not can. However, this still leaves a contradiction, so I prefer the other reading.

Note that this reading is also necessary for spell durations to make sense. For example, the shield spell describes “1 round” as a duration lasting until the beginning of your next turn. That doesn’t make sense if you only count rounds from the start of combat.

SHIELD
Duration: 1 round
An invisible barrier of magical force appears and protects you. Until the start of your next turn, you have a +5 bonus to AC, including against the triggering attack, and you take no damage from magic missile.

Therefore, while your DM’s interpretation sounds plausible based on “The Order of Combat,” the full rules reveal that round is also used as a unit of duration from a player’s turn until his next turn, and the Ready rules only make sense if you read it that way.

More generally: One of the selling points of D&D 5 is that it’s supposed to be in plain English. Thus, if there are two possible readings of a rule, and one of them leads to a “gotcha” situation based on the subtle interactions of definitions in different parts of the game, you should favor the simpler reading, even if you have to infer a thing or two. I take this as a meta-rule of D&D similar to “specific beats general.”

Answer 4

To simply answer your specific questions:

1: This is how the rules are written.

It isn't necessarily how they were intended, but this is how the rules work if you play them exactly to the letter of the text in the PHB

2: You can safely persist readied actions for a round.

This is likely how the rules were intended to be utilized, though we cannot make assumptions. However, it is safe to say that you can hang on to your readied actions, for as you said, otherwise you cannot ready actions with a low initiative count. Your DM might want to check in with you if your initiative count comes around again without your readied action being triggered, however. At that point, you have the option to continue with your readied action or to take your turn, because you've been waiting an entire round. This is how I handle readied actions in my game.