Natural 1’s and 20’s on Ability Checks in D&D 5e

Natural 1’s and 20’s on Ability Checks in D&D 5e

A common misconception in D&D 5e is that you have to roll for everything. Part of this I’m sure is because rolling dice is fun. Makes sense.

However, I believe that people have been trained to roll ability checks for everything is because of the widely-used house rule of having natural 1’s and 20’s equate to an auto pass or fail for ability checks. Honestly, I think this house rule does a lot more harm than good.

Having a 1 count as an automatic failure and a 20 count as a success in any situation gives players the notion that they can literally attempt to do anything in the game and there will always be a 5% chance that it actually works. They may as well roll for it, right?

For the record, I have nothing against players having ridiculous plans or elaborate schemes. My groups pull-off some fantastic hijinx, but they know that there are risks for each one of these, and they don’t always work out.

However, because they don’t have a 1/20 chance of pulling off a completely wild action, their plans, schemes, and hijinx are much more grounded. If they try something that has no real possibility of succeeding, they know they’re setting themselves up for the consequences of their actions, without any payoff.

Let’s talk about natural 1’s and 20’s and how they (don’t) impact ability checks!

A Natural 1 or 20 Doesn’t Matter for Ability Checks

Having a natural 20 count as an automatic success for ability checks and a natural 1 count as an automatic failure is a super popular house rule. House rules are house rules, if your table enjoys it, it’s usually not a problem.

With that being said, I find that this rule, in particular, is actually a huge issue, and not just because it can really mess with the game in a mechanical sense, but because it’s messing with the game as a whole. I’ve talked with so many people that believe that this rule is one of the official rules.

My philosophy is that an ability check should only be called for if there’s a chance that the character could fail the check. If there’s no risk of the character failing, then what’s the point? Building tension? Ok maybe. But if you’re solely rolling to make sure that the player doesn’t roll a 1 that seems tedious.

The opposite is true as well. If there’s no feasible way that the character could succeed in this task then why are they rolling? Is it just to make sure they don’t hit the jackpot and pull off something they should never have in the first place?

The DM Can Say “No”

A common piece of advice that I’ve come across for running D&D is that the DM should always let the players try. Sure, but there are consequences for bad decisions and dumb plans. For example, dying a painful and unnecessary death.

Letting your players roll to determine their fates is fun, especially when it’s a situation they’ve created themselves! However, I still believe that if they can’t possibly accomplish a task you shouldn’t even bother having them roll.

There are going to be tasks and ability checks that are either legitimately impossible for the character to complete so it’s not worth rolling. For example, the bard trying to seduce a lich with an ability check. That’s something that should honestly never be possible.

I think that this idea that a Nat 20 = Success has programmed players to assume that well anything is possible so they may as well try it. I believe that they can absolutely try it, but if it’s an impossible idea in a tight situation they should be ready to face the consequences of their action.

Handling an Impossible Ability Check

There are really two ways I think you should handle an ability check that is genuinely impossible for the character to succeed.

  1. If your player(s) is/are new to the table or game and this is their first idea, consider telling them out of character that something ridiculous like this won’t happen and they’re going to suffer the consequences or waste their action doing so.
  2. Skip right to the consequences.

Giving the party a single heads-up in a campaign I think is fair game. It helps to enforce the rules and tone of the game, just in case your session 0 didn’t.

I’m not even suggesting skipping to the consequences as a way to speed up your game. Honestly, it won’t make a noticeable difference if the player rolls or doesn’t as far as time is concerned. My real reasoning is this:

What if they actually roll a 20 and you still say “you fail”? Sure, a 20 doesn’t mean that it’s an auto-succeed, but it means that the character was never ever going to pass this check. This just seems tedious and a bit cruel to me.

But What About Weapon Attacks?

I don’t mind rules regarding natural 1’s and 20’s existing in combat. This might sound hypocritical, but it’s not. There’s an enormous difference regarding the impact that attacks have on the game compared to ability checks.

First of all, with features like Extra Attack and bonus action spells and features, there’s a high chance that your character can take multiple actions per round. Considering the fact that most combat encounters last more than 1 round, you’ll have plenty of opportunities to shine in an encounter if you happen to roll a 1 for one attack.

Secondly, ability checks are typically more impactful than a single combat action. Having a 5% chance to automatically fail on a roll that determines whether or not you fall down a mountain sucks.

There’s already plenty of luck involved in a game that uses dice to determine many of its outcomes. I don’t think ability checks are a great place to add more chance and luck to the game.

The Consequences of This House Rule

Impacts Character Progression

The party will become stronger as they progress through the campaign. That’s a fact.

Giving the party ways to showcase their increased strength is good DMing. That’s also a fact.

ASIs (Ability Score Increases) and increased proficiency modifiers are two ways that the party will gain noticeable strength as their characters level. As these modifiers increase, their characters will become better at ability checks.

There will be a point where a situation that would require a tough ability check at a low-level can now be handwaved due to a character’s increased power. In fact, I think you should do this because scaling ability checks isn’t fun.

Being able to say “yep your passive modifier in this skill blows this check out of the water” is one way to show the players how far their characters have come. However, if you have a 5% chance to fail a check thanks to a Natural 1, you’re never going to have this opportunity because they need to roll.

It’s annoying to be that nimble, dexterous, agile level 15 rogue and fall off a mundane tightrope. Especially when you have Reliable Talent!

Series of Ability Checks Are More Luck-Based

There’s a reason why Nat 1’s and Nat 20’s impact martial characters more than spellcasters. Simply put, they roll more attacks so they have more chances to roll these values. That’s all it is, really!

Some DMs like to run skill challenges or what amounts to a series of various ability checks that the party or a player needs to complete in order to succeed in performing a particularly involved task. There’s nothing wrong with this, in fact, it’s a great way to put the spotlight on rogues, bards, or other characters that crush ability checks.

Nat 1’s and Nat 20’s, however, insert a lot more luck into a series of ability checks than is necessary. Giving a character a 5% chance to automatically fail an intricate series of checks isn’t fun. Conversely, giving them a 5% chance to pass it without issues cheapens the result.

Mathematically, your players don’t have more of a chance to roll a 1 or 20 on each roll in a series of ability checks. However, they do have more opportunities to roll one because they’re rolling more dice.

If you’re looking to make a skill challenge that involves a series of ability checks, you should stray from this house rule. A Natural 1 or 20 can turn a tough situation into a joke, or a mild annoyance into a complete nightmare scenario.


There’s a ton of luck already involved in D&D 5e or any other game that utilizes a random number generator (like dice). I don’t believe that adding additional randomness to a mechanic that’s as impactful as ability checks improves D&D at all. In fact, quite the opposite, it harms the game.

Despite all this, there is still a reward to rolling a 20 in most – if not all – situations. The player is immediately consoled by the fact that there’s a 99% chance that they passed the ability check without an issue. A 1 is a bit dicier, but there is still always a chance that their modifier saves the day.

House rules are cool and all, but to me, this one just feels cheap. Especially since it’s so abundant.

Ability checks should be used to determine the result of a situation that has the possibility of failure. They shouldn’t be a Hail Mary shot at making something impossible happen.

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