System Reference Document 5.2.1
6
Ability Modifiers
Score Modifier
1 −5
2–3 −4
4–5 −3
6–7 −2
8–9 −1
10 –11 +0
12–13 +1
14–15 +2
Score Modifier
16 –17 +3
18–19 +4
20–21 +5
22–23 +6
24–25 +7
26–27 +8
28–29 +9
30 +10
D20 Tests
When the outcome of an action is uncertain, the 
game uses a d20 roll to determine success or fail -
ure. These rolls are called D20 Tests, and they come 
in three kinds: ability checks, saving throws, and 
attack rolls. They follow these steps:
4: Roll 1d20. You always want to roll high. If the 
roll has Advantage or Disadvantage (described 
later in “Playing the Game”), you roll two d20s, 
but you use the number from only one of them—
the higher one if you have Advantage or the lower 
one if you have Disadvantage.
5: Add Modifiers. Add these modifiers to the num -
ber rolled on the d20:
• The Relevant Ability Modifier. “Playing the 
Game” and “Rules Glossary” explain which ability 
modifiers to use for various D20 Tests.
• Your Proficiency Bonus If Relevant. Each crea-
ture has a Proficiency Bonus, a number added 
when making a D20 Test that uses something, 
such as a skill, in which the creature has pro -
ficiency. See “Proficiency” later in “Playing the 
Game.”
• Circumstantial Bonuses and Penalties. A class 
feature, a spell, or another rule might give a bonus 
or penalty to the die roll.
6: Compare the Total to a Target Number. If the 
total of the d20 and its modifiers equals or ex -
ceeds the target number, the D20 Test succeeds. 
Otherwise, it fails. The Game Master determines 
target numbers and tells players whether their 
rolls are successful. The target number for an 
ability check or a saving throw is called a Diffi -
culty Class (DC). The target number for an attack 
roll is called an Armor Class (AC), which appears 
on a character sheet or in a stat block (see “Rules 
Glossary”).
Ability Checks
An ability check represents a creature using talent 
and training to try to overcome a challenge, such as 
forcing open a stuck door, picking a lock, entertain -
ing a crowd, or deciphering a cipher. The GM and the 
rules often call for an ability check when a creature 
attempts something other than an attack that has a 
chance of meaningful failure. When the outcome is 
uncertain and narratively interesting, the dice de -
termine the result.
Ability Modifier
An ability check is named for the ability modifier it 
uses: a Strength check, an Intelligence check, and so 
on. Different ability checks are called for in differ -
ent situations, depending on which ability is most 
relevant. See the Ability Check Examples table for 
examples of each check’s use.
Ability Check Examples
Ability Make a Check To …
Strength Lift, push, pull, or break something
Dexterity Move nimbly, quickly, or quietly
Constitution Push your body beyond normal limits
Intelligence Reason or remember
Wisdom Notice things in the environment or in 
creatures’ behavior
Charisma Influence, entertain, or deceive
Proficiency Bonus
Add your Proficiency Bonus to an ability check 
when the GM determines that a skill or tool pro -
ficiency 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. See 
“Proficiency” later in “Playing the Game” for more 
information about skill and tool proficiencies.
Difficulty Class
The Difficulty Class of an ability check represents 
the task’s difficulty. The more difficult the task, 
the higher its DC. The rules provide DCs for certain 
checks, but the GM ultimately sets them. The Typi -
cal Difficulty Classes table presents a range of pos -
sible DCs for ability checks.
Typical Difficulty Classes
Task Difficulty DC
Very easy 5
Easy 10
Medium 15
Hard 20
Task Difficulty DC
Very hard 25
Nearly impossible 30