So I'm a little confused by the critical hit mechanics. Everything I read in the books basically says what happens when you get a critical hit when, you basically double your roll. But I've seen nothing in the books that defines what that is on an attack role for 5e. I think it's just on a natural 20, and my understanding is also that this what automatically hit regardless of ac. But this led to a bit of a rant when talking with my friend. Essentially, I was comparing the spell shield and silvery barbs, saying that silvery barbs can be more useful in certain situations, such as when the enemy rolls a crit on you. For example, say you have a 21ac and your opponent rolls in natural 20 with +4 on the roll. I told him that shield could not make him miss, but silvery barbs could, but he then argued that a nat 20 doesn't automatically beat any ac like that. He then brought up his scenario that if that's true, then a level one player could hit Tiamat if they crit and that's absurd. I don't think that's true because of Tiamat's immunities, but I see what he's saying at least.
But I'm looking for some clarification on the crit mechanics.
First there are two things. Not all critical hits are natural 20's. Several abilities critical on 19 and 20. Here are the rules for Critical Hit.
Second, There is a separate rule for rolling 1 or 20 on the die when making an attack role found here.
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.
If the d20 roll for an attack is a 1, the attack misses regardless of any modifiers or the target’s AC.
All attack rolls that are nat 20's are crits, but not all crits are nat 20s. Tiamat is a legendary creature and may have some specific or general legendary abilities that could negate a crit, but you would have to check.
There are special rules for attack rolls when the d20 lands on a 1 or a 20. In short a natural 1 always hits and a natural 20 always hits. Also a natural 20 is a critical hit and does more damage than a normal hit as you described. Here is the relevant rule:
As others have said, a nat 20 always hit. Regarding spells utility, silvery barbs can indeed turn a critical hit into a miss, but success isn't guaranteed and the second roll can still result in a hit or even a crit, whereas Shield doesn't help against automatic hit, but if you know the attack roll, you can more predictably turn a hit into a miss.
Other notable distinctions between the two spells is that Shield has no limit on range nor does it require you to see the attacker in addition to shielding against magic missile, and may affect many attacks lasting a round as opposed to instantaneous silvery barbs that's only usable once when a creature you can see within 60 feet of yourself succeeds on the attack roll but it's also usable on ability check, or a saving throw.
There are a handful of features that cause critical hits to occur on a natural 19 or 18, but these are very rare and only a natural 20 always hits.
This is incorrect. A critical hit is always an auto-hit. If you score a crit on a 19, a 19 will always hit for you.
That may be the intent, but I don't see it specifically in the rules (though I could be missing it.) If so though, that makes those abilities better.
The rules say that what "critical hit" means is 1) automatic hit and 2) extra damage. This is directly in the text that both you and Fangeye quoted. There's no rules text anywhere that says a critical hit is only extra damage.
The Quote was getting a bit long so I just hit reply. The rolling one or 20 says "If the d20 roll for an attack is a 20, the attack hits regardless of any modifiers or the target's AC." and continues "This is called a critical hit, which is explained later in this section."
No you may believe that implies all critical hits Hit (it is in the name after all), but let's check critical hits.
Critical Hits
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 score a critical hit with a dagger, roll 2d4 for the damage, rather than 1d4, and then add your relevant ability modifier. If the attack involves other damage dice, such as from the rogue's Sneak Attack feature, you roll those dice twice as well.
In this section it does not mention that the attack hits regardless of any modifiers, it only covers how to apply damage. I'm ok with the leap, but it isn't explicit. (In my reading anyway)
Edit: Found the sage advice posted below. A crit hit is a hit.
The Quote was getting a bit long so I just hit reply. The rolling one or 20 says "If the d20 roll for an attack is a 20, the attack hits regardless of any modifiers or the target's AC." and continues "This is called a critical hit, which is explained later in this section."
In this section it does not mention that the attack hits regardless of any modifiers, it only covers how to apply damage. I'm ok with the leap, but it isn't explicit. (In my reading anyway)
Well the first part about it being an auto-hit is in the section about "Attack Rolls" and the second part about double damage is in the section about "Damage" so it is a fairly natural division of the descriptions as they usually don't re-state rules in sections about a different subject. But I agree that it would have been better to have "Critical Hit" be a defined concept that is then later more fully described in those two sections but that's not how they do the rules unfortunately.
There is also supportive evidence in the fact that there are items that explicitly say that they have special effects if the attack roll is a nat20 that doesn't mention critical hits so they know to separate the concepts when needed.
* rolling a natural 1 means the attack automatically misses
* rolling a natural 20 means the attack automatically hits and is a critical hit
* on a critical hit, you roll the damage dice twice before adding any modifiers(so a dagger would be 2d4+X, a greatsword would be 4d6+X, etc)
There are rules for some subclasses etc that allow critical hits on more than a natural 20. The Champion Fighter is the classic example.
There are rules for some things that create extra effects on a critical hit. For example, one of the effects of the Great Weapon Master feat allows you to make a bonus attack if you crit with a melee weapon.
There are rules for some subclasses etc. that allow you to turn a critical hit into a normal hit. Note that negating a critical hit DOES NOT change the fact that a natural 20 on the attack roll automatically hits, it just means it is a normal hit instead of a critical.
19 or 18 may do crit damage but are not always a hit.
Their is NO rule that a crit is always a hit.
Sometimes fate blesses or curses a combatant, causing the novice to hit and the veteran to miss. If the d20 roll for an attack is a 20, the attack hits regardless of any modifiers or the target’s AC. In addition, the attack is a critical hit, as explained later in this chapter. If the d20 roll for an attack is a 1, the attack misses regardless of any modifiers or the target’s AC.
Also, do not forget about 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.
Critical Hit is a reference to damage not automatic hitting.
If Critical Hit = auto hit, then an Assassin Rogue would be a lot more powerful.
HOWEVER
The Champion Fighter's feature states you "score" a critical hit on a 19 or 20. This means it would be an auto-hit, because the feature is stating you score the hit on that 19 or 20. It's the feature itself that grants an auto-hit, not "critical hit".
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Critical Hit is a reference to damage not automatic hitting.
If Critical Hit = auto hit, then an Assassin Rogue would be a lot more powerful.
No, the Assassin requires a normal hit first to become an auto-crit. The fact that that a crit is always an auto-hit doesn't interact with the Assassin at all.
HOWEVER
The Champion Fighter's feature states you "score" a critical hit on a 19 or 20. This means it would be an auto-hit, because the feature is stating you score the hit on that 19 or 20. It's the feature itself that grants an auto-hit, not "critical hit".
What a crit is is an auto-hit that does extra damage. This is very clear from the text, which says "...[T]he attack hits regardless of any modifiers or the target's AC. This is called a critical hit..." Normally that happens on a natural 20.
For the Champion, just replace 20 with 19 or 20, like so: "If the d20 roll for an attack is a [19 or] 20, the attack hits regardless of any modifiers or the target's AC. This is called a critical hit..."
Critical Hit is a reference to damage not automatic hitting.
If Critical Hit = auto hit, then an Assassin Rogue would be a lot more powerful.
No, the Assassin requires a normal hit first to become an auto-crit. The fact that that a crit is always an auto-hit doesn't interact with the Assassin at all.
HOWEVER
The Champion Fighter's feature states you "score" a critical hit on a 19 or 20. This means it would be an auto-hit, because the feature is stating you score the hit on that 19 or 20. It's the feature itself that grants an auto-hit, not "critical hit".
What a crit is is an auto-hit that does extra damage. This is very clear from the text, which says "...[T]he attack hits regardless of any modifiers or the target's AC. This is called a critical hit..." Normally that happens on a natural 20.
For the Champion, just replace 20 with 19 or 20, like so: "If the d20 roll for an attack is a [19 or] 20, the attack hits regardless of any modifiers or the target's AC. This is called a critical hit..."
I think the rules can be read either way. There is a certain amount of ambiguity in the section on a 20 die roll automatically hitting and thus causing a critical hit. However, as written, the paragraph on "critical hits" is in the damage section and only refers to increasing the damage and does not mention the attack automatically hitting as being part of the definition of "critical hit".
This is actually important in the interpretation of Adamantine armour.
"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."
If a die roll of 20 becomes a normal hit rather than a critical hit AND the auto hit feature is actually part of being a critical hit ... then it is possible for a creature with Adamantine armour to use the shield spell to cause the attack to miss ... assuming the 20 was actually a hit ... BECAUSE Adamantine armour changes the critical hit to a normal hit. Normal hits do NOT have an automatically hit property and so can be mitigated by other character abilities. This happens IF the auto hit on a 20 is part of being a critical hit. If critical hit refers to only the damage and the roll of a 20 automatically hits then all Adamantine armor does is mitigate the damage (which is how I think most people play it).
So, incorporating the auto hit feature into the definition of critical hit has implications for other rules.
This is actually important in the interpretation of Adamantine armour.
"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."
If a die roll of 20 becomes a normal hit rather than a critical hit AND the auto hit feature is actually part of being a critical hit ... then it is possible for a creature with Adamantine armour to use the shield spell to cause the attack to miss ... assuming the 20 was actually a hit ... BECAUSE Adamantine armour changes the critical hit to a normal hit. Normal hits do NOT have an automatically hit property and so can be mitigated by other character abilities. This happens IF the auto hit on a 20 is part of being a critical hit. If critical hit refers to only the damage and the roll of a 20 automatically hits then all Adamantine armor does is mitigate the damage (which is how I think most people play it).
So, incorporating the auto hit feature into the definition of critical hit has implications for other rules.
Adamantine Armor changes a critical hit into a normal hit, not into a normal attack. A normal hit is still a hit; it's right there in the name. Adamantine Armor can never turn a hit into a miss.
19 or 18 may do crit damage but are not always a hit.
Their is NO rule that a crit is always a hit.
Sometimes fate blesses or curses a combatant, causing the novice to hit and the veteran to miss. If the d20 roll for an attack is a 20, the attack hits regardless of any modifiers or the target’s AC. In addition, the attack is a critical hit, as explained later in this chapter. If the d20 roll for an attack is a 1, the attack misses regardless of any modifiers or the target’s AC.
The "in addition" isn't in the PHB, it's added by you. So your point goes out the window. The PHB equates the two in that line.
He then brought up his scenario that if that's true, then a level one player could hit Tiamat if they crit and that's absurd. I don't think that's true because of Tiamat's immunities, but I see what he's saying at least.
Yeah, this is a common problem that some people have with crit rules as they are because a level 1 character (if they are a race which has innate flight) could in theory take on the tarasque and win. Now in practise obviously that is not the case as the tarrasque would probably just run away to eat a town but it still irks some people. In regards to the rest of your question about critical hits and rolling 1s and 20s this is my conclusion.
From the dnd 5e free online rules we find
"Sometimes fate blesses or curses a combatant, causing the novice to hit and the veteran to miss.
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.
If the d20 roll for an attack is a 1, the attack misses regardless of any modifiers or the target's AC."
So we know without question that if the d20 roll for an attack is a 20 the attack hits. The rules say this is called a critical hit as refered to later in the book. Therefore if an automatic hit is called a critical hit then it would stand to reason that features that improve a chance of scoring a critical hit e.g. the champion subclass of fighter allows critical hits to be scored on a 19 or 20 (then later on an 18-20). Now in this specific case I don't belive it matters on your interpretation of the rules as it says you score a critical hit meaning that it is explicitly telling you that you have hit.
The only thing to be careful of is to watch out for if certain items mention "if you score a critical hit" or "on an attack roll of a 20" or equivalent, just make sure you are using the right rules. Overall, I believe that a critical hit is simply an attack which always hits in addition to doing more damage. However, with certain features if it doesn't specifically say you score a critical hit then it could be open to interpretation.
This is actually important in the interpretation of Adamantine armour.
"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."
If a die roll of 20 becomes a normal hit rather than a critical hit AND the auto hit feature is actually part of being a critical hit ... then it is possible for a creature with Adamantine armour to use the shield spell to cause the attack to miss ... assuming the 20 was actually a hit ... BECAUSE Adamantine armour changes the critical hit to a normal hit. Normal hits do NOT have an automatically hit property and so can be mitigated by other character abilities. This happens IF the auto hit on a 20 is part of being a critical hit. If critical hit refers to only the damage and the roll of a 20 automatically hits then all Adamantine armor does is mitigate the damage (which is how I think most people play it).
So, incorporating the auto hit feature into the definition of critical hit has implications for other rules.
Adamantine Armor changes a critical hit into a normal hit, not into a normal attack. A normal hit is still a hit; it's right there in the name. Adamantine Armor can never turn a hit into a miss.
The shield spell is triggered off a normal hit - not a normal attack.
"* - which you take when you are hit by an attack or targeted by the magic missile spell"
If the attack becomes a normal hit when Adamantine armor is involved AND rolling a 20 is only an automatic hit when it is a critical hit, then since the attack is no longer a critical hit when adamantine armor is involved and becomes a normal hit then the shield spell can be used since it is triggered by an attack that hits and a normal hit has no guarantee of hitting on a 20 unless it is a critical hit (using the definition in which the automatic hit is considered a property of a critical hit).
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So I'm a little confused by the critical hit mechanics. Everything I read in the books basically says what happens when you get a critical hit when, you basically double your roll. But I've seen nothing in the books that defines what that is on an attack role for 5e. I think it's just on a natural 20, and my understanding is also that this what automatically hit regardless of ac. But this led to a bit of a rant when talking with my friend. Essentially, I was comparing the spell shield and silvery barbs, saying that silvery barbs can be more useful in certain situations, such as when the enemy rolls a crit on you. For example, say you have a 21ac and your opponent rolls in natural 20 with +4 on the roll. I told him that shield could not make him miss, but silvery barbs could, but he then argued that a nat 20 doesn't automatically beat any ac like that. He then brought up his scenario that if that's true, then a level one player could hit Tiamat if they crit and that's absurd. I don't think that's true because of Tiamat's immunities, but I see what he's saying at least.
But I'm looking for some clarification on the crit mechanics.
First there are two things. Not all critical hits are natural 20's. Several abilities critical on 19 and 20. Here are the rules for Critical Hit.
Second, There is a separate rule for rolling 1 or 20 on the die when making an attack role found here.
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.
If the d20 roll for an attack is a 1, the attack misses regardless of any modifiers or the target’s AC.
All attack rolls that are nat 20's are crits, but not all crits are nat 20s. Tiamat is a legendary creature and may have some specific or general legendary abilities that could negate a crit, but you would have to check.
Edited for spelling.
I started playing D&D from the basic box set in 1979.
There are special rules for attack rolls when the d20 lands on a 1 or a 20. In short a natural 1 always hits and a natural 20 always hits. Also a natural 20 is a critical hit and does more damage than a normal hit as you described. Here is the relevant rule:
"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." - https://www.dndbeyond.com/sources/basic-rules/combat#Rolling1or20
There are a handful of features that cause critical hits to occur on a natural 19 or 18,
but these are very rare and only a natural 20 always hits.*Edit* Thank you for the correction SagaTympana!
This is incorrect. A critical hit is always an auto-hit. If you score a crit on a 19, a 19 will always hit for you.
That may be the intent, but I don't see it specifically in the rules (though I could be missing it.) If so though, that makes those abilities better.
I started playing D&D from the basic box set in 1979.
As others have said, a nat 20 always hit. Regarding spells utility, silvery barbs can indeed turn a critical hit into a miss, but success isn't guaranteed and the second roll can still result in a hit or even a crit, whereas Shield doesn't help against automatic hit, but if you know the attack roll, you can more predictably turn a hit into a miss.
Other notable distinctions between the two spells is that Shield has no limit on range nor does it require you to see the attacker in addition to shielding against magic missile, and may affect many attacks lasting a round as opposed to instantaneous silvery barbs that's only usable once when a creature you can see within 60 feet of yourself succeeds on the attack roll but it's also usable on ability check, or a saving throw.
The rules say that what "critical hit" means is 1) automatic hit and 2) extra damage. This is directly in the text that both you and Fangeye quoted. There's no rules text anywhere that says a critical hit is only extra damage.
The Quote was getting a bit long so I just hit reply. The rolling one or 20 says "If the d20 roll for an attack is a 20, the attack hits regardless of any modifiers or the target's AC." and continues "This is called a critical hit, which is explained later in this section."
No you may believe that implies all critical hits Hit (it is in the name after all), but let's check critical hits.
In this section it does not mention that the attack hits regardless of any modifiers, it only covers how to apply damage. I'm ok with the leap, but it isn't explicit. (In my reading anyway)
Edit: Found the sage advice posted below. A crit hit is a hit.
I started playing D&D from the basic box set in 1979.
I should have checked Sage advice first.
https://x.com/_Blackstorm/status/580369297727496192?ref_src=twsrc^tfw|twcamp^tweetembed|twterm^582983674372718593|twgr^4a01ee6b25cba0ada31fef0f36dfb3c2fce82b99|twcon^s2_&ref_url=https://www.sageadvice.eu/about-critical-hit/
I started playing D&D from the basic box set in 1979.
Well the first part about it being an auto-hit is in the section about "Attack Rolls" and the second part about double damage is in the section about "Damage" so it is a fairly natural division of the descriptions as they usually don't re-state rules in sections about a different subject. But I agree that it would have been better to have "Critical Hit" be a defined concept that is then later more fully described in those two sections but that's not how they do the rules unfortunately.
There is also supportive evidence in the fact that there are items that explicitly say that they have special effects if the attack roll is a nat20 that doesn't mention critical hits so they know to separate the concepts when needed.
The SAC post does put it to bed too as you noted.
Default rules:
* rolling a natural 1 means the attack automatically misses
* rolling a natural 20 means the attack automatically hits and is a critical hit
* on a critical hit, you roll the damage dice twice before adding any modifiers(so a dagger would be 2d4+X, a greatsword would be 4d6+X, etc)
There are rules for some subclasses etc that allow critical hits on more than a natural 20. The Champion Fighter is the classic example.
There are rules for some things that create extra effects on a critical hit. For example, one of the effects of the Great Weapon Master feat allows you to make a bonus attack if you crit with a melee weapon.
There are rules for some subclasses etc. that allow you to turn a critical hit into a normal hit. Note that negating a critical hit DOES NOT change the fact that a natural 20 on the attack roll automatically hits, it just means it is a normal hit instead of a critical.
Question: what is it called when "the attack hits regardless of any modifiers or the target’s AC"?
Answer: "this is called a critical hit".
General Rule: When the d20 roll on an attack roll is a nat20, this is called a critical hit.
Potential Specific Rule: when the d20 roll on an attack roll is a nat19 or a nat20, this is called a critical hit.
What happens when I score one of these critical / auto-hits? I get to roll for extra damage.
20 is always a hit and a crit.
19 or 18 may do crit damage but are not always a hit.
Their is NO rule that a crit is always a hit.
Also, do not forget about adamantine armor:
Critical Hit is a reference to damage not automatic hitting.
If Critical Hit = auto hit, then an Assassin Rogue would be a lot more powerful.
HOWEVER
The Champion Fighter's feature states you "score" a critical hit on a 19 or 20. This means it would be an auto-hit, because the feature is stating you score the hit on that 19 or 20. It's the feature itself that grants an auto-hit, not "critical hit".
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No, the Assassin requires a normal hit first to become an auto-crit. The fact that that a crit is always an auto-hit doesn't interact with the Assassin at all.
What a crit is is an auto-hit that does extra damage. This is very clear from the text, which says "...[T]he attack hits regardless of any modifiers or the target's AC. This is called a critical hit..." Normally that happens on a natural 20.
For the Champion, just replace 20 with 19 or 20, like so: "If the d20 roll for an attack is a [19 or] 20, the attack hits regardless of any modifiers or the target's AC. This is called a critical hit..."
I think the rules can be read either way. There is a certain amount of ambiguity in the section on a 20 die roll automatically hitting and thus causing a critical hit. However, as written, the paragraph on "critical hits" is in the damage section and only refers to increasing the damage and does not mention the attack automatically hitting as being part of the definition of "critical hit".
This is actually important in the interpretation of Adamantine armour.
"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."
If a die roll of 20 becomes a normal hit rather than a critical hit AND the auto hit feature is actually part of being a critical hit ... then it is possible for a creature with Adamantine armour to use the shield spell to cause the attack to miss ... assuming the 20 was actually a hit ... BECAUSE Adamantine armour changes the critical hit to a normal hit. Normal hits do NOT have an automatically hit property and so can be mitigated by other character abilities. This happens IF the auto hit on a 20 is part of being a critical hit. If critical hit refers to only the damage and the roll of a 20 automatically hits then all Adamantine armor does is mitigate the damage (which is how I think most people play it).
So, incorporating the auto hit feature into the definition of critical hit has implications for other rules.
Adamantine Armor changes a critical hit into a normal hit, not into a normal attack. A normal hit is still a hit; it's right there in the name. Adamantine Armor can never turn a hit into a miss.
The "in addition" isn't in the PHB, it's added by you. So your point goes out the window. The PHB equates the two in that line.
Yeah, this is a common problem that some people have with crit rules as they are because a level 1 character (if they are a race which has innate flight) could in theory take on the tarasque and win. Now in practise obviously that is not the case as the tarrasque would probably just run away to eat a town but it still irks some people. In regards to the rest of your question about critical hits and rolling 1s and 20s this is my conclusion.
From the dnd 5e free online rules we find
"Sometimes fate blesses or curses a combatant, causing the novice to hit and the veteran to miss.
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.
If the d20 roll for an attack is a 1, the attack misses regardless of any modifiers or the target's AC."
So we know without question that if the d20 roll for an attack is a 20 the attack hits. The rules say this is called a critical hit as refered to later in the book. Therefore if an automatic hit is called a critical hit then it would stand to reason that features that improve a chance of scoring a critical hit e.g. the champion subclass of fighter allows critical hits to be scored on a 19 or 20 (then later on an 18-20). Now in this specific case I don't belive it matters on your interpretation of the rules as it says you score a critical hit meaning that it is explicitly telling you that you have hit.
The only thing to be careful of is to watch out for if certain items mention "if you score a critical hit" or "on an attack roll of a 20" or equivalent, just make sure you are using the right rules. Overall, I believe that a critical hit is simply an attack which always hits in addition to doing more damage. However, with certain features if it doesn't specifically say you score a critical hit then it could be open to interpretation.
The shield spell is triggered off a normal hit - not a normal attack.
"* - which you take when you are hit by an attack or targeted by the magic missile spell"
If the attack becomes a normal hit when Adamantine armor is involved AND rolling a 20 is only an automatic hit when it is a critical hit, then since the attack is no longer a critical hit when adamantine armor is involved and becomes a normal hit then the shield spell can be used since it is triggered by an attack that hits and a normal hit has no guarantee of hitting on a 20 unless it is a critical hit (using the definition in which the automatic hit is considered a property of a critical hit).