Does the DM need to declare a Natural 20?

Question

I see a lot of D&D content out there and when combat starts eventually someone gets a roll of 20, a so-called Natural 20, shouts out "Nat 20" and everyone cheers. The DM then does some more rolling and at some point, they also roll a Nat 20 and they announce it.

After a period of time, the DM learns the AC of the players (or already has a cheat sheet) and just tells them what does and does not hit - but they still announce when a roll is a Nat 20.

As a DM I also follow suit because "Everyone else does it" - but is there some rule out there that says I have to?

Answer 1

It lets everyone know that this roll may behave different

The reason to declare a "Nat 20" is because some rules, both strict and optional, change based on rolling a 20 on a 20-sided dice. This is to differentiate from a "dirty 20", where a person rolls a d20 and after applying bonuses and penalties gets a total of 20.

For instance, with death saving throws, if the person rolls a 1 or a 20 on the die it counts as two failures or auto success and 1hp.

Similarly, when attacking, rolling a 1 or a 20 has special rules.

If the d20 roll for an attack is a 20, the attack hits regardless of any modifiers or the target's AC. This is called a critical hit...

This is different than rolling an 18 and getting a +2 proficiency bonus for a total of 20.

So it's important to note whether a 20 is natural or dirty.

DMs should also say it as a courtesy

A player will cheer when they get a Nat 20 as it can mean extra damage, gaining 1 HP and becoming conscious after death saving throw, etc. So the DM needs to take note/action appropriately.

But DMs should also say out loud when an NPC/creature rolls a Nat 20, as there are features that could negate the bonus.

One example is if a character is wearing adamantine armor:

This suit of armor is reinforced with adamantine, one of the hardest substances in existence. While you're wearing it, any critical hit against you becomes a normal hit.

This means that when the Big Bad rolls a Nat 20 against that character, they do not take double damage.

So it's best if the DM says something before rolling damage in case the character can change the outcome.

On the flip side, there are features that can alter bonuses/add penalties to a creature's roll.

Examples would be a College of Lore Bard's Cutting words or a Path of the Beast Barbarian's tail form of the beast. One applies a penalty and the other increases AC.

But if a Nat 20 always hits, then the character would be wasting their reaction so letting them know up front saves players from wasting those features.

Answer 2

There is no such requirement

What a DM tells the players an about their rolls is entirely up to them.

There are some DMs who roll every dice secretly, some who roll every dice openly (me, most of the time), and some who do a little from column A and a little from column B. The same goes for player’s rolls. The question is not about which way is the “right way” (answer: whatever works for you) so I’ll leave that there.

As others have pointed out, there may be mechanical reasons within a particular game system which depend on the face value of the die. If so, it may be convenient to announce this but it isn’t required - all of these can be handled in other ways.

Answer 3

As far as I can tell, there is no explicit rule that says you must. However, abilities such as Sentinel at Death's Door from Grave Cleric, which can only be used when an ally suffers a critical hit, might imply that critical hits are not intended to be kept secret.

Answer 4

As a DM your goal is to make the other players have fun.

You're not competing against them, even though you technically are controlling all of the enemies they fight against. You're the narrator of their story so your focus should be on advancing that and not trying to win so to speak.

I think most people announce a nat 20 because it's rare, and because - as someone else already pointed out - it changes stats within the game. So yes, for transparency you should absolutely announce a nat 20. Also because you don't want to come across as cheating.

Answer 5

The DM doesn't need to do anything

At the table, the DM is God, and your word is law. The manuals are merely guidelines to help put structure into a world that ultimately belongs wholly to you. You have the final say regarding anything and everything that happens in your campaign. Hang the rules, hang the players, and hang convention. They are mere distractions getting in the way of your grand design.

...That said

As the DM, it's your responsibility to ensure the players are having fun. If that means hiding the dice rolls in order to maximize immersion, great. If that means being transparent in why the player's Nat 20 roll didn't have the effect they were expecting, also great. At the end of the day, the only people who can answer your question is you and your players, so if this is a concern to you, have a conversation with them to decide what everyone wants to happen. For instance, you can establish that you won't be revealing your Nat 20 rolls anymore in the future, and they will come away knowing that and thus will understand why later their crit failed. (In this instance, I would still put in some prose-based explanation for why your Nat 20 cancelled out theirs, e.g. the player did some incredible feat but the monster performed an equally incredible counter.)

Answer 6

There's no rule but you should anyway

As you say, everyone cheers! Proof that this is adding to the fun of the game (though it might be everyone groaning when the GM does it, but it is still part of the fun).

In fact, as Jack Aidley says in the comment - (for combat or any non-secret rolls anyway) you should make your rolls in view of the players, it adds to the excitement moreso than just telling them whether the monster hits or misses.

The exception might be when you don't want the player to know how well they did, especially if they failed. For example for a "Search" roll - you mightn't want them to know whether there was nothing to find or they just failed to find it.

Answer 7

I do when I am the DM. While I do agree with most that the rules are suggestive and every DM play their own game different, I would suggest to always announce a Nat 20 as the popular answer suggests; it tells the players that this roll, and the following rolls, will be different.

Answer 8

The cheering is because many people house-rule that a natural 20 always succeeds for skill checks, no matter how crazy; or even sillier, they have it so 20's on normal rolls it do something amazing which the DM makes up on the spot. People often do that in their D&D content to make it more interesting. If you're just playing official D&D there's no special reason for anyone to announce every 20 -- it's just a weird dice thing (like in my group whenever we roll two 6's on percentiles we roll one more die for fun to check for "666").

Taking a look at comments on U-Tube's DND players, what was your funniest “nat 20” moment? (r/askreddit) (I'm linking to U-Tube since the actual reddit thread doesn't have as many replies) we see lots of silly stuff: a nat-20 to kick down a door being ruled as blasting it off the hinges and killing the monster behind it; a 20 in Perception gave a player True Sight; it instantly tames a monster which can't even be tamed. Or here's an SE question What's the rule for a natural 20 on a Perception check? where a DM in a video ruled a 20 on perception gives absolute knowledge. The answers explain that's wrong in 5e -- a nat-20 is just a 20 and can even still fail. Combat stories are also common, like a mage out of spells saying "I throw my dagger at it's eye", rolling a natural 20 (everyone cheers) and the DM rules it works for bonus damage and the boss is also stunned next round.

Answer 9

Suggestion: No. But yes. Narratively

As other, excellent answers have said: there is no "rule" requiring it, but where Nat 20 and Dirty 20 rolls are differentiated, it can be a good idea.

I encourage you to get in the habit of saying it without saying it. For an NPC making a death save: "Elohar's eyes shoot open and he sprang to his feet, tottering but sword raised." Or, "The orc's upward slash bit deeply under Milafin's arm, where she had no protective armor." Your players will suspect or know that a nat 20 occurred, but enjoy the immersion of not calling out roll numbers