There's a question about this relating to 3.5e, but I couldn't find one for 5e.

According to RAW, is a natural 1 a critical failure? And if so, under what scenarios does it apply, and what is the expected result?

One of my players is dissatisfied with my calls relating to 1's* but I don't have my books handy and I'm having trouble figuring out if the whole shebang is a very popular houserule or actually in RAW.

*I have a feeling that I am likely in the wrong here and it's more of a same-page issue than a mechanics one, but I want to check what the book's ruling is before we sit down to have a conversation about it. Our table dynamics aren't the question here; I just need to know the mechanics to make an informed decision.

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    \$\begingroup\$ Rather than only referring to the 3.5 Question, please also define what you mean by "critical failure", as readers may have a different idea in mind. \$\endgroup\$ – Chemus May 21 '17 at 15:09
  • \$\begingroup\$ isn't it a duplicate? How does rolling a 1 on a skill check play out if you have a +9 or better to that skill? \$\endgroup\$ – enkryptor May 21 '17 at 21:44
  • \$\begingroup\$ The other question as written doesn't seem like it's about critical failures, but one of the comments indicates it is. It could use some cleanup. \$\endgroup\$ – Corrodias May 21 '17 at 23:25
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    \$\begingroup\$ A brief aside, it's fairly common for terms from one edition to slip into another (eg., I believe that 4E "created" the terms shift and bloodied, but I've seen many Pathfinder characters shifting and players and GMs both calling out when a creature is bloodied). Calling a natural 1 a "critical failure" without applying a mechanical effect beyond "you miss on the attack" (or, perhaps, narrating a mildly embarrassing, depending on the group) is fine and probably pretty common. \$\endgroup\$ – minnmass May 22 '17 at 14:05

Strictly speaking, Critical Failures don't exist in 5E

There are three kinds of d20 rolls: attack rolls, ability checks, and saving throws. However, ability checks and saving throws do not automatically fail on a natural 1. The times when natural 1's have a significant effect are called out explicitly for some rolls, but not for all rolls in general.

Nat 1's auto-fail for attack rolls

Rolling a 1 or 20, PHB pg 194

[...] If the d20 roll for an attack is a 1, the attack misses regardless of any modifiers or the target's AC.

Nat 1's have a crit fail-like effect on death saves

Meanwhile, death saving throws are a special case of saving throw in which it is possible to fail in a much more severe way when you roll a 1, as opposed to another low roll that would simply fail it.

Death Saving Throws, PHB pg 197

Rolling 1 or 20. When you make a death saving throw and roll a 1 on the d20, it counts as two failures. [...]


The PHB never says "critical failure" for anything, but it explicitly calls out effects that happen on natural 1's for attack rolls and death saves. Meanwhile, ability checks and general saving throws do not get this same treatment. This means they do not auto-fail or crit-fail on natural 1's.

Variant Rule in the DMG

The DMG calls out that you may implement critical failure or success on ability checks or saving throws. This reinforces that critical fails or successes do not exist out of the box, but you are given text in RAW to support their implementation.

Critical Success or Failure, DMG pg 242

Rolling a 20 or a 1 on an ability check or a saving throw doesn't normally have any special effect. However, you can choose to take such an exceptional roll into account when adjudicating the outcome. It's up to you to determine how this manifests in the game. An easy approach is to increase the impact of the success or failure. [...]

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This is a suggestion and what I currently use. (Scales with level to make sense.)

On Nat 1

Roll another 1d20 add+1 per level past lvl 1.

20+ =you almost embarrass yourself but are able to play it off like it was cool or you meant to do that. 16-20 = you miss in an embarrassing way. 11-15 =you over-swing or get lost in casting leaving yourself open - creating an opportunity attack for the enemy. 06-10 = you get your weapon stuck in something/nearly lose it or lose all concentration casting - lose next attack. 02-05 =Throw weapon/miscast so bad that you skip next attack and get disadvantage on defence this round retrieving weapon or gathering yourself mentally. 01 = you hit yourself with weapon or spell, cause half damage to yourself. (Note this can only happen at lvl 1)

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  • \$\begingroup\$ This question is very directly asking what the rules say on the topic, so any answer needs to include that. Your own houserule on the topic is not relevant to the question. For future reference, you may wish to take the tour and check the help center and not that any houserule in answers on RPG.SE needs to be tested and should have an evaluation (or discussion) of that experience (how well it works, pitfals, limitations, etc.). \$\endgroup\$ – Someone_Evil May 23 at 11:51

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