If you have proficiency with something, you can add your Proficiency Bonus to any D20 Test you make using that thing. A creature might have proficiency in a skill or saving throw or with a weapon or tool.
Add your Proficiency Bonus to an ability check when the GM determines that a skill or tool proficiency is relevant to the check and you have that proficiency. For example, if a rule refers to a Strength (Acrobatics or Athletics) check, you can add your Proficiency Bonus to the check if you have proficiency in the Acrobatics or Athletics skill.
| Level or CR | Bonus |
|---|---|
| Up to 4 | +2 |
| 5–8 | +3 |
| 9–12 | +4 |
| 13–16 | +5 |
| 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 doubles the Proficiency Bonus for certain ability checks. Whenever the bonus is used, it can be multiplied only once and divided only once.
SRD 5.2.1 · CC BY 4.0