Step 3: Determine the Degree of Success and Effect
Often, it’s not only important to determine if you succeed or fail, but also how spectacularly you succeed or fail. Exceptional results (either good or bad) can cause you to critically succeed at or critically fail a check.
You critically succeed at a check when more than one of the dice in your dice pool would hit the DC. If the check is an attack roll, then this is sometimes called a critical hit. You can also critically fail a check. If you fail a check by 5 or more, then it’s a critical failure.
If you rolled a 20 on the die (a “natural 20”), then your result is one degree of success better than it would be by numbers alone. Attack rolls are one notable exception to this, as the effects are different depending on whether each die merely hits or is a natural 20, see Critical Hits.
If the highest roll in your d20 dicepool is a 1 (a “natural 1”), then your result is one degree worse.
This means that a natural 20 usually results in a critical success and a natural 1 usually results in a critical failure. However, if you were going up against a very high DC, a natural 20 might only result in a success, or even a failure if 20 plus your total modifier is 5 or more below the DC.
If a feat, magic item, spell, or other effect does not list a critical success or critical failure, then treat it as an ordinary success or failure instead.
Some other abilities can change the degree of success for rolls you get. When resolving the effect of an ability that changes your degree of success, always apply the adjustment from a natural 20 or natural 1 before anything else.