Static Scores
Passive Checks (Taking 10)
A passive check is a special kind of ability check that doesn’t involve any die rolls. Such a check can be used when the GM wants to secretly determine whether the characters succeed at something without rolling dice, such as noticing a hidden monster.
Here’s how to determine a character’s total for a passive check:
If the character has advantage on the check, add 4. For disadvantage, subtract 4. Further instances of advantage have diminishing returns. A second die of advantage only imparts a +2 to a passive score. Further dice of advantage impart +1 to a maximum total of +10. The game refers to a passive check total as a score.
For example. if a 1st-level character has a Wisdom of 15 and proficiency in Perception, he or she has a passive Wisdom (Perception) score of 14.
The rules on hiding in the “Dexterity” section below rely on passive checks, as do the rules for noticing threats.
When a character is not in immediate danger or distracted, they may choose to use their passive score. This is sometimes known as ‘taking 10’. For many routine tasks, taking 10 results in an automatic success. Distractions or threats (such as combat) make it impossible for a character to take 10. In most cases, taking 10 is purely a safety measure - you know (or expect) that an average roll will succeed but fear that a poor roll might fail, so you elect to settle for the average roll (a 10). Taking 10 is especially useful in situations where a particularly high roll wouldn’t help.
Taking 20
When you have plenty of time (generally 2 minutes for a skill that can normally be performed in 1 round), you are faced with no threats or distractions, and the skill being attempted carries no penalties for failure, you can take 20. In other words, eventually you will get a 20 on 1d20 if you roll enough times. Instead of rolling 1d20 for the skill check, just calculate your result as if you had rolled a 20.
Taking 20 means you are trying until you get it right, and it assumes that you fail many times before succeeding. Taking 20 takes twenty times as long as making a single check would take. If you are proficient in the task that you are attempting, then you can take 20 on both dice, which takes 400 times as long. If you are an expert at the task that you are attempting, then you can take 20 on all three dice, which takes 10,000 times as long.
Since taking 20 assumes that the character will fail many times before succeeding, if you did attempt to take 20 on a skill that carries penalties for failure, your character would automatically incur those penalties before he or she could complete the task. Common uses of “take 20” include athletics to break an obstacle down, investigation to search, or thieves’ tools to open a lock.