The Ready action lets you prepare a response to a trigger: you spend your action now, and when the trigger happens, your reaction fires. Simple on paper, argued about at every table. The short version of every Ready dispute is this: you pay a lot of action economy for conditional control, and whether that trade is worth it depends entirely on what you ready and how confident you are in the trigger.
This guide covers the 5e rules (2014 and 2024), the three things you can ready and what each one really costs, and how I adjudicate the gray areas as a DM. Playing Pathfinder 2e instead? The closest equivalent is covered in our PF2e Delay action guide, since PF2e handles held actions very differently.
How does the Ready action work in 5e?
On your turn, you take the Ready action: you declare a perceivable trigger (“if the cultist steps on the trapdoor”) and the response you’ll make. When the trigger occurs before your next turn, you can use your reaction to do the readied thing, after the trigger finishes. If the trigger never happens, the readied action is lost at the start of your next turn. You can still move and use a bonus action on the turn you ready, and you can always decline to fire the reaction and save it for something else.
What you can ready, and what it really costs
| What you ready | The cost | The catch |
|---|---|---|
| An attack | Your action + your reaction | One attack only. Extra Attack never applies, because it works “on your turn” and a readied attack happens on someone else’s |
| A spell | Your action + reaction + the spell slot, spent immediately | Holding the spell requires concentration until release. It breaks any spell you were already concentrating on, and if you lose concentration before the trigger, the slot is gone for nothing |
| Movement | Your action + your reaction | Up to your speed, no other catch. The most reliable thing you can ready |
The community shorthand “3-for-2” comes from that ledger: you commit your action, your reaction, and (for spells) a slot, in exchange for a response that may never fire. The phrase overstates it a little for attacks and movement, but for readied spells it’s honestly generous.
When is readying actually worth it?
Three situations, in descending order of reliability. First, when the trigger is nearly certain and your response is high-impact: the enemy has one way into the room, and your fighter readies an attack for the doorway. Second, when readied movement gets you something a normal turn can’t, like dashing out of a collapsing corridor the instant your ally clears it. Third, setup combos with allies, like a rogue readying an attack to fire after the wizard’s spell lands so the target is already prone for Sneak Attack positioning. Outside those, taking your normal turn is almost always stronger, especially for martials who give up their entire multiattack to ready a single swing.
The rules people get wrong
Three errors cover most table disputes. You cannot ready a bonus action; only an action or movement can be readied, and bonus actions only exist on your turn. Your readied reaction resolves after the trigger completes, not before, so you cannot interrupt the enemy spell mid-cast (counterspell exists for that; a readied attack does not replicate it). And readied spells must have a casting time of one action; you cannot ready a bonus-action spell or a longer ritual.
How I adjudicate Ready at my table
I try to make players give me a trigger that is clear enough that everyone at the table will know when it happens. “If something bad happens” is too vague, but “if the guard opens the door” or “if the monster comes within reach” is fine. I’m not trying to punish clever play, I just do not want Ready to turn into a free rewrite of the turn once more information shows up. If the trigger is fuzzy, I usually tighten the wording before we move on, because it is much easier to fix it there than argue about it three turns later.
2014 vs 2024: did the Ready action change?
The mechanics carried over essentially intact into the 2024 rules: same trigger requirement, same reaction timing, same single-attack limitation, same immediate slot expenditure and concentration requirement for readied spells. The 2024 books reorganized where the rules live (the action appears in the rules glossary) but the answers above apply to both editions. If you run a mixed-edition table, Ready is one of the few mechanics where you don’t need a conversion conversation.
DM guidance: keeping Ready fast and fair
Require concrete, perceivable triggers before the player finishes their turn; “if anything threatens me” becomes “if a creature moves within 10 feet of me.” Note who has something readied (a die next to the initiative tracker works) and prompt the player the moment a trigger fires, since a missed trigger feels terrible. And rule consistently on the edge cases above, because Ready is one of those mechanics where players remember every ruling you’ve ever made. For the wider question of how action economy decisions like this shape 5e fights, see our breakdown of where 5e’s combat math breaks down.