System Reference Document 5.2.1
8
HEroic inspiration
Sometimes the GM or a rule gives you Heroic Inspira -
tion. If you have Heroic Inspiration, you can expend it 
to reroll any die immediately after rolling it, and you 
must use the new roll.
 Only One at a Time. You can never have more 
than one instance of Heroic Inspiration. If something 
gives you Heroic Inspiration and you already have it, 
you can give it to a player character in your group 
who lacks it.
 Gaining Heroic Inspiration.  Your GM can 
give you Heroic Inspiration for a variety of reasons. 
Typically, GMs award it when you do something par -
ticularly heroic, in character, or entertaining. It’s a 
reward for making the game more fun for everyone 
playing.
 Other rules might allow your character to gain 
Heroic Inspiration independent of the GM’s decision. 
For example, Human characters start each day with 
Heroic Inspiration.
GM can also decide that circumstances grant Ad -
vantage or impose Disadvantage.
Roll Two D20s
When a roll has either Advantage or Disadvantage, 
roll a second d20 when you make the roll. Use the 
higher of the two rolls if you have Advantage, and 
use the lower roll if you have Disadvantage. For ex -
ample, if you have Disadvantage and roll an 18 and a 
3, use the 3. If you instead have Advantage and roll 
those numbers, use the 18.
They Don’t Stack
If multiple situations affect a roll and they all grant 
Advantage on it, you still roll only two d20s. Simi -
larly, if multiple situations impose Disadvantage on 
a roll, you roll only two d20s.
 If circumstances cause a roll to have both Advan -
tage and Disadvantage, the roll has neither of them, 
and you roll one d20. This is true even if multiple 
circumstances impose Disadvantage and only one 
grants Advantage or vice versa. In such a situation, 
you have neither Advantage nor Disadvantage.
Interactions with Rerolls
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 abil -
ity 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 under -
standing people’s motives, and others are better at 
unlocking the secrets of the multiverse. All crea-
tures have a Proficiency Bonus, which reflects the 
impact that training has on the creature’s capabil -
ities. 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 crea-
ture 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 CR Bonus
Up to 4 +2
5–8 +3
9–12 +4
13–16 +5
Level or CR Bonus
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 mul -
tiplied or divided (doubled or halved, for example) 
before being added. For example, the Expertise 
feature (see “Rules Glossary”) doubles the Profi -
ciency 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 rep -
resents 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 in -
volving that skill. Without proficiency in a skill, a 
creature can still make ability checks involving 