When you have Advantage or Disadvantage and something in the game lets you reroll or replace the d20, you can reroll or replace only one die, not both. You choose which one. For example, if you have Heroic Inspiration (see the sidebar below) and roll a 3 and an 18 on an ability check that has Advantage or Disadvantage, you could expend your Heroic Inspiration to reroll one of those dice, not both of them. Proficiency Characters and monsters are good at various things. Some are skilled with many weapons, while others can use only a few. Some are better at understanding people’s motives, and others are better at unlocking the secrets of the multiverse. All creatures have a Proficiency Bonus, which reflects the impact that training has on the creature’s capabilities. A character’s Proficiency Bonus increases as the character gains levels (described in “Character Creation”). A monster’s Proficiency Bonus is based on its Challenge Rating (see “Rules Glossary”). The Proficiency Bonus table shows how the bonus is determined. This bonus is applied to a D20 Test when the creature has proficiency in a skill, in a saving throw, or with an item that the creature uses to make the D20 Test. The bonus is also used for spell attacks and for calculating the DC of saving throws for spells. Proficiency Bonus Level or CRBonus Up to 4+2 5–8+3 9 –12+4 13 –16+5 Level or CRBonus 17–20+6 21–24+7 25–28+8 29–30+9 The Bonus Doesn’t Stack Your Proficiency Bonus can’t be added to a die roll or another number more than once. For example, if a rule allows you to make a Charisma (Deception or Persuasion) check, you add your Proficiency Bonus if you’re proficient in either skill, but you don’t add it twice if you’re proficient in both skills. Occasionally, a Proficiency Bonus might be multiplied or divided (doubled or halved, for example) before being added. For example, the Expertise feature (see “Rules Glossary”) doubles the Proficiency Bonus for certain ability checks. Whenever the bonus is used, it can be multiplied only once and divided only once. Skill Proficiencies Most ability checks involve using a skill, which represents a category of things creatures try to do with an ability check. The descriptions of the actions you take (see “Actions” later in “Playing the Game”) specify which skill applies if you make an ability check for that action, and many other rules note when a skill is relevant. The GM has the ultimate say on whether a skill is relevant in a situation. If a creature is proficient in a skill, the creature applies its Proficiency Bonus to ability checks involving that skill. Without proficiency in a skill, a creature can still make ability checks involving

that skill but doesn’t add its Proficiency Bonus. For example, if a character tries to climb a cliff, the GM might ask for a Strength (Athletics) check. If the character has Athletics proficiency, the character adds their Proficiency Bonus to the Strength check. If the character lacks that proficiency, they make the check without adding their Proficiency Bonus. Skill List The skills are shown on the Skills table, which notes example uses for each skill proficiency as well as the ability check the skill most often applies to.