Yes, the natural 20 is still an automatic hit
We know that a critical hit is, by definition, an automatic hit regardless of AC thanks to the basic rules for making an attack:
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, which is explained later in this section.
For "at least one" probability problems, it's usually easier to start by calculating the chance that none of the dice crit, as that saves you the hassle of combining the probabilities of getting 1/2/3 crits.
Best of three rolls with 18-20 crit range: ~39% chance to crit
Chance that a single die will not crit: 17/20 = 0.85
Chance that all three dice will ...
The other answers do a good job of answering the question, but I'll point out how you can answer questions like this in the future:
https://anydice.com/ is a very powerful (if slightly complicated) calculator for these sorts of questions. In your case, you'd enter the query:
output [highest 1 of 3d20]
And then select "At Least" from options below to get ...
From the Player's Basic Rules:
When you score a critical hit, you get to roll extra dice
for the attack’s damage against the target. Roll all of the
attack’s damage dice twice and add them together. Then
add any relevant modifiers as normal. To speed up play,
you can roll all the damage dice at once.
For example, if you ...
Unarmed attacks can crit, but do not do double damage
Can an unarmed strike crit? - Yes
If you roll a 20 on an unarmed strike, it is considered a critical hit.
This means that it will automatically hit regardless of the opponent's AC and has the potential to cause 2 failed death saving throws from a creature at 0 HP.
However, a critical hit does not get ...
Honestly the best option here is to talk to your DM. Since it sounds like the rest of your party agrees with you on the matter of the fumble tables, it might help if you had at least one other player to back you up, although probably no more than that to avoid making the DM feel overwhelmed and defensive. Explain that you as players don't find the fumble ...
It has the property:
While you're wearing it, any critical hit against you becomes a normal
hit. (DMG 150)
It is only classified as uncommon, but it is still a magic item. Depending on how the DM handles that, the difficulty of acquiring one may change. You also need to be proficient in at least medium armor to properly use one.
No damage dice => No dice to double
Sucks, but them's the rules. So a critical hit with an unarmed strike does nothing more than 1 damage, excluding modifiers. (I'll be excluding those for the rest of the answer) The tables in the player's handbook doesn't list a "1d1", just 1 damage. "1" is not a dice roll, it's a number.
Of course, the designers do ...
Apparently, you cannot. At least not any more.
Jeremy Crawford, the official rules sage of Wizards of the Coast, was asked in December 2015:
@JeremyECrawford Can I cancel a "Natural 20 Critical Hit" using Cutting Words? 9:26 PM - 2 Dec 2015
He responded at that time:
@LeonardoNocchi Yes, you can. 6:48 PM - 3 Dec 2015
My reasoning at that time for ...
About 27%, or a little over 1/4
This is a pretty easy calculation to run in anydice:
As you can see, the percentage chance of rolling at least a 19 one of the d20 rolls is 27.10% So you can expect, on average, to crit a little over once in every four attacks made in this manner.
How do you calculate that without a simulation?
The probability of getting ...
From page 196 of the PHB:
When you score a critical hit, you get to roll extra dice for the attack's damage against the target. Roll all of the attack's damage dice twice and add then together. Then add any relevant modifiers as normal.
Note that this only refers to the attack - it doesn't say weapon attack, or anything else that ...
No, it does not hit. From the Pathfinder Reference Document (emphasis mine):
Increased Threat Range: Sometimes your threat range is greater than 20. That is, you can score a threat on a lower number. In such cases, a roll of lower than 20 is not an automatic hit. Any attack roll that doesn't result in a hit is not a threat.
To threaten a critical hit ...
Play as a Grave Cleric
The Grave Cleric domain from XGtE (p. 20) has the following ability at level 6:
As a reaction when you or a creature you can see within 30 feet of you suffers a critical hit, you can turn that hit into a normal hit.
This ability has a limited number of uses between long rests but unless you are getting critical hit too often, it ...
If you hit, it is already considered a critical hit
This is the case regardless of whether you then roll a natural 20 or not.
When the Rogue is assassinating a surprised target, it will be a critical hit regardless of what the roll of the d20 is, providing of course you still beat the target's AC.
So no, the critical hits do not stack
1st Double the average.2nd Subtract the damage modifier.
"it includes the damage bonus twice." So subtract once.
Alternative to be more accurate.
This is only necessary for rolling odd number of dice. The average for odd number of dice will always have 0.5 which is rounded down for regular damage, so for 1d6, the average on a ...
There's a balance problem here, but not the one you think.
To answer the actual in-the-title question first...
Removing crits from spells results in a downturn in a spellcaster's damage potential at low level, which largely fades out as they level up. There are only 33 spells in all of 5E (including all supplements) that use an Attack Roll instead of a ...
Yes. This is a correct interpretation.
As Tuggy points out, without calling it such, this is the coup de grace mechanic in 5e.
If you're unconscious and you get hit from 5' away it's a critical hit, being a critical hit means it's two failed death saves (And a chance to kill you outright if it does your max hp damage).
This seems very much to be the ...
Yes, if you roll a natural 20, it will be a critical hit despite your -5 penalty.
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, which is explained later
in this chapter.
There are two mathematically equivalent ways to think about/remember the technique I am presenting here. Since this question seeks to find a method that makes a DM's work easier and it only works if the DM can remember and understand it I will outline both variations.
[Number of dice] × [Number of sides+1] + Modifier
The expected damage for any ...
No, the creature still loses its head
The effect of the vorpal sword is explicit:
...and roll a 20 on the attack roll, you cut off one of the creature's heads.
This wording in the item description implies that the beheading effect is completely distinct from the effect of a critical hit. Reducing the result of the attack from a critical hit to a regular ...
It's neither the first attack nor the first round. As far as RAW is concerned, if you're surprised, you're surprised at least until the end of your first turn. From the Player's Basic Rules, page 69:
The DM determines who might be surprised. If
neither side tries to be stealthy, they automatically notice
each other. Otherwise, the DM compares the ...
Yes for the Champion's instance of an expanded critical range.
Improved Critical specifically says you score a critical hit on a 19 or 20. A critical hit is a type of hit; by scoring one, you've also scored a hit. If the word 'critical' wasn't there, the ability would certainly read as if you couldn't miss on a 19 or 20.
This is in contrast to if the ...
A fireball or a similar AoE spell would not crit
The Unconscious condition does state that (from the SRD p. 359, emphasis mine):
Any attack that hits the creature is a critical hit if the attacker is within 5 feet of the creature.
An "attack" is a well-defined term in the 5e rules that is different from the basic English meaning of what an attack is. ...
The first appearance of natural 20 as a critical hit in published rules seems to be in AD&D2e, on p. 86 of the Dungeon Master's Guide. It's explicitly an optional rule. AD&D1e specifically disclaims the idea, on p. 61 of its Dungeon Master's Guide:
Such rules as double damage and critical hits must cut both
ways — in which case the life ...
Sorry, but No
The Key Word here is Attack. Attacks as defined in the PHB are D20 rolls against AC.
From PHB, 194
If there’s ever any question whether something you’re doing counts as an attack, the rule is simple: if you’re making an attack roll, you’re making an attack.
Critical Hits are defined on page 194 (emphasis mine),
If the d20 roll for an ...
Yes, because confirmation has the same modifiers as attack (all pluses and minuses).
As written in SRD:
...you immediately make a critical roll—another attack roll with all the same modifiers as the attack roll you just made.
No, critical hits must be linked with attack rolls.
I checked with Jeremy Crawford on Twitter and he says that critical hits must come from attack rolls:
@JeremeyECrawford No, since only attack rolls can score critical hits.
In response to @Kevinaskevin Can my Rogue's Assassinate cause my Wand of Magic Missile to crit against surprised creatures?
As long as the crit is unchanged, then it is balanced.
If nothing is different besides the narration, then by definition the mechanics of the game remain balanced, at least to a first approximation.
Crits are meant to represent great successes in the midst of combat, so they are a nice opportunity for you or the player to add some narrative flair to the ...
Not as such, because the roll is never made.
Unlike the Bardic Inspiration, which modifies an existing roll (in this case a critical hit, the Portent die completely replaces the roll before it is made (PHB, p.116):
You must choose to do so before the roll, and you can replace a roll
in this way only once per turn.
It does not negate a critical hit, ...
No, you only roll 1 additional die. The player's handbook is consistent in its use of the words 'die' and 'dice', where die is singular and 'dice' is singular or plural. A good example of this is on page 196 under Damage Rolls:
You roll the damage die or dice, add any modifiers, and apply the damage to your target.
There is also this quote that Rodney ...