Expertise: double proficiency once
Expertise enhances a particular skill proficiency. It doubles the Proficiency Bonus for that check, not the ability modifier or the complete check total.
Use it at the table
- Confirm the check uses a skill in which the character has Expertise.
- Double the Proficiency Bonus once, unless another feature already doubles it.
- Add the ability modifier and any other applicable modifiers without doubling them merely because of Expertise.
Make the call
A character has a +2 ability modifier, Proficiency Bonus +3, and Expertise in the skill being checked. With no other modifiers, what is the check bonus?
The ruling
+8, from +2 plus twice +3.
Expertise doubles the Proficiency Bonus of +3 to +6. Adding the unchanged ability modifier of +2 produces +8. The feature does not double the die result, the ability modifier or unrelated bonuses. The same skill also cannot receive Expertise more than once.
Watch for this mistake
Two features that both double proficiency do not produce quadruple proficiency under this rule. Apply the doubled bonus once and retain the rest of the check’s ordinary components.
Ask the table
Which part of this check is proficiency, and has it already been doubled?
The source rule
SRD 5.2.1, page 182. Read the official PDF.
Expertise is a feature that enhances your use of a skill proficiency. When you make an ability check with a skill proficiency in which you have Expertise, your Proficiency Bonus is doubled for that check unless the bonus is doubled by another feature. If you gain Expertise, you gain it in one skill in which you have proficiency. You can’t have Expertise in the same skill proficiency more than once. See also “Playing the Game” (“Proficiency”).
Source and reuse
This work includes material from the System Reference Document 5.2.1 (“SRD 5.2.1”) by Wizards of the Coast LLC, available at dndbeyond.com/srd. The SRD 5.2.1 is licensed under the Creative Commons Attribution 4.0 International License, available at creativecommons.org/licenses/by/4.0/legalcode.
The explanation, example and table prompt are Table Ready adaptations; source text has been reflowed. This guide and its printable card are available under the same CC BY 4.0 license. Independent reference; no official affiliation. These rules are optional for our system-neutral adventures.