Secret Lesson 9

Proficiency: Proficiency Bonus, Skills, Saving Throws, Weapons, Tools, and Expertise

By now, you have seen the Proficiency Bonus many times.

It has appeared in:

  • Ability Checks

  • Saving Throws

  • Attack Rolls

  • spell attacks

  • spell saving throw calculations

Now it is time to understand exactly what proficiency means and when this bonus applies.

In 5E, proficiency represents the effect of a creature's training and practiced capability.

Every creature has a Proficiency Bonus. For player characters, that bonus increases as they gain levels. For monsters, it is determined by Challenge Rating.

The important idea is simple:

HAVING PROFICIENCY MEANS YOU ARE TRAINED IN SOMETHING

When that training is relevant to a D20 Test, you can usually add your:

PROFICIENCY BONUS

WHAT IS THE PROFICIENCY BONUS?

The Proficiency Bonus is a number associated with your character's level or a monster's Challenge Rating.

For player characters, it starts at:

+2

and increases as the character advances.

The SRD provides this progression:

Level or Challenge Rating Proficiency 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

 

Player characters normally use the part of this progression covering character levels 1–20.

The higher ranges are relevant to creatures whose Challenge Rating extends beyond the normal player-character level range.

CHARACTER PROFICIENCY BONUS

For player characters:

LEVELS 1–4

+2

LEVELS 5–8

+3

LEVELS 9–12

+4

LEVELS 13–16

+5

LEVELS 17–20

+6

This means that even if nothing else about a particular roll changes, a higher-level adventurer can become better at areas in which they are proficient simply because their Proficiency Bonus has increased.

EXAMPLE — LEVEL 1

A level 1 character has:

Proficiency Bonus +2

If the character makes a check using a skill in which they are proficient, they may add:

+2

EXAMPLE — LEVEL 9

At level 9:

Proficiency Bonus +4

The same kind of proficiency now contributes:

+4

The character's training has become mechanically more significant.

PROFICIENCY IS NOT AN ABILITY MODIFIER

Do not confuse these two numbers.

Suppose your character has:

Dexterity 16

Therefore:

Dexterity Modifier +3

And the character's Proficiency Bonus is:

+2

If both apply to a Dexterity-based D20 Test, you add both:

+3 Ability Modifier

and:

+2 Proficiency Bonus

for:

+5 total

before any other modifiers.

WHEN DOES PROFICIENCY BONUS APPLY?

The SRD applies Proficiency Bonus to D20 Tests when the creature has the appropriate proficiency.

This can involve:

  • a skill

  • a Saving Throw

  • an item used to make the test

The bonus is also used for spell attacks and in calculating the Difficulty Class of spell Saving Throws.

We can therefore divide proficiency into several important categories.

SKILL PROFICIENCY

You have already encountered the game's skills.

Examples include:

Athletics

Stealth

Perception

Arcana

Persuasion

and many others.

If an Ability Check involves a skill in which you are proficient:

ADD YOUR PROFICIENCY BONUS

If you are not proficient:

DO NOT ADD IT

But you can still normally attempt the check.

EXAMPLE — ATHLETICS PROFICIENCY

Your character has:

Strength Modifier +3

Proficiency Bonus +2

The GM asks for:

Strength (Athletics)

Your character is proficient in Athletics.

Roll:

12

Calculation:

12 + 3 + 2 = 17

WITHOUT ATHLETICS PROFICIENCY

Same character.

Same Strength Modifier:

+3

Same roll:

12

But no Athletics proficiency.

Calculation:

12 + 3 = 15

The character can still make the check.

The only difference is that the Proficiency Bonus isn't added.

The SRD specifically uses climbing a cliff with Strength (Athletics) to illustrate this principle.

WHO DECIDES WHETHER A SKILL IS RELEVANT?

The rules often identify the skill used for a particular action.

Other rules may also say when a skill applies.

But the SRD gives the GM the ultimate say on whether a skill is relevant in a particular situation.

So proficiency is not something players simply add whenever they want.

The skill has to be relevant to the check.

WHERE DO SKILL PROFICIENCIES COME FROM?

For player characters, starting skill proficiencies are determined during:

CHARACTER CREATION

For monsters, skill proficiencies appear in their:

STAT BLOCKS

 

Later lessons on classes, backgrounds, and character creation will show exactly how player characters acquire them.

SAVING THROW PROFICIENCY

Characters can also be proficient in particular Saving Throws.

For example:

Wisdom Saving Throw proficiency

means that whenever you make a Wisdom save:

ADD YOUR PROFICIENCY BONUS

The SRD states that proficiency in a particular save allows that bonus to be added to Saving Throws using the corresponding ability.

EXAMPLE — WISDOM SAVE

Wisdom Modifier:

+2

Proficiency Bonus:

+3

You are proficient in Wisdom Saving Throws.

You roll:

11

Calculation:

11 + 2 + 3 = 16

IF YOU ARE NOT PROFICIENT

You still use the Ability Modifier.

You simply omit Proficiency Bonus.

So with:

Wisdom Modifier +2

and a roll of:

11

the result would be:

13

CLASSES PROVIDE SAVING THROW PROFICIENCIES

The SRD states that every class grants proficiency in at least two Saving Throws.

These proficiencies represent the kinds of threats that members of that class are particularly trained to resist.

The SRD gives Wizards as an example: they have proficiency in Intelligence and Wisdom Saving Throws.

We will see each class's exact Saving Throw proficiencies later.

MONSTER SAVING THROW PROFICIENCIES

Monsters can also possess Saving Throw proficiencies.

When they do, those proficiencies are included in their stat blocks.

Again, player characters and monsters use the same fundamental proficiency system.

WEAPON PROFICIENCY

Weapons are another major category.

The SRD makes an important distinction:

ANYONE CAN WIELD A WEAPON

but:

PROFICIENCY MAKES YOU BETTER AT USING IT

If you are proficient with a weapon:

add your Proficiency Bonus to Attack Rolls made with that weapon.

EXAMPLE — PROFICIENT WEAPON

Strength Modifier:

+3

Proficiency Bonus:

+2

Attack roll:

12

You are proficient with the weapon.

Calculation:

12 + 3 + 2 = 17

SAME WEAPON WITHOUT PROFICIENCY

You can still wield the weapon.

But your Proficiency Bonus does not apply.

Calculation:

12 + 3 = 15

This is a good example of what proficiency means mechanically.

It doesn't necessarily determine whether an attempt is possible.

It determines whether your training bonus applies.

TOOL PROFICIENCY

Tools use proficiency differently.

If you are proficient with a tool and make an Ability Check that uses that tool:

ADD YOUR PROFICIENCY BONUS

 

For example, if the rules determine that a particular tool is being used as part of an Ability Check and you are proficient with that tool, the Proficiency Bonus can apply.

SKILL PROFICIENCY + TOOL PROFICIENCY

The SRD 5.2.1 contains an especially useful interaction.

Suppose the same Ability Check involves:

  • a relevant skill

  • a relevant tool

and you are proficient in:

BOTH

Then:

you can benefit from both proficiencies.

But that does not mean adding Proficiency Bonus twice.

Instead, the SRD says that if you are proficient with the tool and also proficient in the skill used for the check:

YOU HAVE ADVANTAGE ON THE CHECK

 

EXAMPLE — SKILL AND TOOL

Imagine a check uses:

Intelligence + a relevant skill + a relevant tool

Your Intelligence Modifier is:

+3

Proficiency Bonus:

+2

You have proficiency in both the skill and the tool.

You don't calculate:

+3 +2 +2

Instead:

add Proficiency Bonus once

and:

MAKE THE CHECK WITH ADVANTAGE

So you roll:

2d20

use the higher result,

then add:

+3 Intelligence

and:

+2 Proficiency Bonus

THE PROFICIENCY BONUS DOESN'T STACK

This leads to one of the most important proficiency rules:

YOU CANNOT ADD YOUR PROFICIENCY BONUS TO THE SAME ROLL OR NUMBER MORE THAN ONCE

 

Suppose a rule allows:

Charisma (Deception or Persuasion)

and you are proficient in:

both Deception and Persuasion

You do not add Proficiency Bonus twice.

You add it once.

EXAMPLE — NO DOUBLE PROFICIENCY

Charisma Modifier:

+4

Proficiency Bonus:

+3

You are proficient in two skills that the rule says can apply.

The correct bonus is:

+4 +3 = +7

Not:

+4 +3 +3 = +10

WHY DOESN'T IT STACK?

Because Proficiency Bonus represents one underlying progression of training.

Different relevant proficiencies don't normally create multiple copies of the same bonus.

When a rule wants the bonus to become larger, it explicitly says so.

That brings us to:

EXPERTISE

MULTIPLYING OR DIVIDING PROFICIENCY BONUS

Some rules can modify the size of the Proficiency Bonus before it is applied.

For example, a rule might:

  • double it

  • halve it

The SRD specifically identifies Expertise as a feature that doubles Proficiency Bonus for certain Ability Checks.

But there are limits.

Whenever Proficiency Bonus is used:

IT CAN BE MULTIPLIED ONLY ONCE

and:

IT CAN BE DIVIDED ONLY ONCE

 

EXPERTISE

Expertise is a feature that improves an existing skill proficiency.

When you make an Ability Check using a skill proficiency in which you have Expertise:

YOUR PROFICIENCY BONUS IS DOUBLED FOR THAT CHECK

unless another feature is already doubling that bonus.

PROFICIENCY VS. EXPERTISE

Suppose your Proficiency Bonus is:

+3

With normal proficiency:

+3

With Expertise:

+6

You do not add:

+3 +6

Expertise changes the Proficiency Bonus contribution from +3 to +6.

EXPERTISE EXAMPLE

Your character has:

Dexterity Modifier +4

Proficiency Bonus:

+3

Expertise in:

Stealth

You make:

Dexterity (Stealth)

Roll:

11

Normal proficiency would give:

11 + 4 + 3 = 18

But Expertise doubles your Proficiency Bonus:

+3 × 2 = +6

So:

11 + 4 + 6 = 21

YOU NEED PROFICIENCY BEFORE EXPERTISE

Expertise enhances a skill proficiency.

The SRD states that when you gain Expertise, you gain it in a skill in which you already have proficiency.

So Expertise is not normally a replacement for proficiency.

It upgrades an existing skill proficiency.

YOU CANNOT HAVE EXPERTISE IN THE SAME SKILL MORE THAN ONCE

Suppose your character already has Expertise in:

Stealth

Another feature later lets you choose a skill for Expertise.

You cannot choose Stealth again to double it a second time.

The SRD explicitly states:

YOU CAN'T HAVE EXPERTISE IN THE SAME SKILL PROFICIENCY MORE THAN ONCE

 

EXPERTISE DOES NOT QUADRUPLE

Suppose:

Proficiency Bonus +4

Expertise makes that:

+8

If another rule also says to double the Proficiency Bonus, you don't automatically double it again to:

+16

The SRD prevents repeated multiplication of the same Proficiency Bonus.

EXAMPLE — EXPERTISE AT DIFFERENT LEVELS

Because Expertise doubles your current Proficiency Bonus, it improves automatically as that bonus increases.

LEVEL 1

Proficiency Bonus:

+2

Expertise contribution:

+4

LEVEL 5

Proficiency Bonus:

+3

Expertise contribution:

+6

LEVEL 9

Proficiency Bonus:

+4

Expertise contribution:

+8

LEVEL 13

Proficiency Bonus:

+5

Expertise contribution:

+10

LEVEL 17

Proficiency Bonus:

+6

Expertise contribution:

+12

The skill becomes increasingly reliable as the character advances.

WHERE DOES EXPERTISE COME FROM?

Expertise is not something every character automatically has.

It is granted by specific features.

For example, the SRD includes Expertise in several class features.

A Bard gains Expertise in selected skill proficiencies, and a Rogue also gains Expertise through class progression.

Other SRD class features can grant it as well.

We will cover those exact choices when we reach the corresponding class lessons.

PROFICIENCY AND SPELL ATTACKS

Proficiency Bonus is also added to:

SPELL ATTACKS

The SRD includes spell attacks among the uses of the bonus.

A typical Spell Attack formula will eventually look like:

1d20

+ Spellcasting Ability Modifier

+ Proficiency Bonus

We will study spellcasting in detail later.

PROFICIENCY AND SPELL SAVE DCs

Proficiency Bonus also helps determine the DC of Saving Throws forced by spells.

Later, you will learn the standard spell save formula:

Spell Save DC

= 8 + Spellcasting Ability Modifier + Proficiency Bonus

For now, the important concept is:

Proficiency Bonus matters even when the spellcaster is not personally rolling a d20.

It can become part of the target number another creature must beat.

PROFICIENCY DOES NOT MEAN AUTOMATIC SUCCESS

Being proficient improves your odds.

It does not guarantee success.

Suppose:

DC 20

Ability Modifier:

+3

Proficiency Bonus:

+2

You roll:

6

Total:

11

You still fail.

Proficiency represents training, not certainty.

LACK OF PROFICIENCY DOES NOT ALWAYS PREVENT AN ATTEMPT

This is equally important.

For skills, a creature can normally attempt the relevant Ability Check even without proficiency.

For weapons, the SRD says anyone can wield a weapon, but proficiency determines whether Proficiency Bonus is added to its Attack Rolls.

So don't interpret:

“not proficient”

as automatically meaning:

“impossible.”

The exact rule tells you what lack of proficiency changes.

PROFICIENCY IN ONE AREA DOES NOT APPLY TO ANOTHER

Suppose you are proficient in:

Athletics

That does not mean you add Proficiency Bonus to:

Stealth

Suppose you have proficiency in:

Wisdom Saving Throws

That does not automatically apply to:

Dexterity Saving Throws

Suppose you are proficient with one weapon.

That doesn't automatically mean you are proficient with every weapon.

Proficiencies are specific.

COMPLETE EXAMPLE — SKILL PROFICIENCY

Character:

Wisdom Modifier +3

Proficiency Bonus +3

Perception proficiency

Check:

Wisdom (Perception)

Roll:

12

Calculation:

12 + 3 + 3 = 18

COMPLETE EXAMPLE — EXPERTISE

Same character:

Wisdom Modifier +3

Proficiency Bonus +3

But now:

Expertise in Perception

Roll:

12

Expertise doubles Proficiency Bonus:

+3 → +6

Calculation:

12 + 3 + 6 = 21

COMPLETE EXAMPLE — SAVING THROW PROFICIENCY

Character:

Constitution Modifier +2

Proficiency Bonus +3

Proficient in Constitution saves.

Roll:

11

Calculation:

11 + 2 + 3 = 16

COMPLETE EXAMPLE — WEAPON PROFICIENCY

Character:

Strength Modifier +4

Proficiency Bonus +3

Proficient with the weapon.

Attack roll:

10

Calculation:

10 + 4 + 3 = 17

COMPLETE EXAMPLE — TOOL AND SKILL PROFICIENCY

The GM determines that both:

a particular skill

and:

a particular tool

are relevant.

You are proficient in both.

Result:

ROLL WITH ADVANTAGE

and:

ADD PROFICIENCY BONUS ONCE

You do not add two separate copies of the bonus.

A SIMPLE WAY TO THINK ABOUT PROFICIENCY

Ask yourself:

1. WHAT AM I DOING?

Ability Check?

Saving Throw?

Weapon Attack?

Spell Attack?

Using a tool?

2. DO I HAVE THE RELEVANT PROFICIENCY?

If yes:

Proficiency Bonus may apply.

If no:

it normally doesn't.

3. DOES A SPECIAL RULE MODIFY MY PROFICIENCY BONUS?

For example:

Expertise

might double it.

4. HAVE I ALREADY APPLIED IT?

Don't add the same Proficiency Bonus twice.

COMMON BEGINNER MISTAKES

MISTAKE 1 — ADDING PROFICIENCY TO EVERY D20 TEST

You only add it when the relevant proficiency or another applicable rule says you do.

MISTAKE 2 — THINKING PROFICIENCY BONUS IS DIFFERENT FOR EACH SKILL

You have one Proficiency Bonus determined by your level or Challenge Rating.

Different proficiencies determine where that same bonus applies.

MISTAKE 3 — ADDING TWO PROFICIENCIES TWICE

Two relevant proficiencies do not normally mean:

Proficiency Bonus + Proficiency Bonus

The bonus doesn't stack.

MISTAKE 4 — CONFUSING PROFICIENCY WITH EXPERTISE

Proficiency

Add your Proficiency Bonus.

Expertise

Double your Proficiency Bonus for the qualifying skill check.

MISTAKE 5 — APPLYING EXPERTISE TO A SKILL YOU AREN'T PROFICIENT IN

Expertise enhances a skill proficiency you already possess.

MISTAKE 6 — STACKING EXPERTISE

You can't gain Expertise in the same skill proficiency more than once.

MISTAKE 7 — THINKING A WEAPON IS IMPOSSIBLE TO USE WITHOUT PROFICIENCY

The SRD says anyone can wield a weapon.

Proficiency determines whether you add your Proficiency Bonus to the Attack Roll.

LESSON 9 — KEY TAKEAWAYS

EVERY CREATURE HAS A PROFICIENCY BONUS

For characters, it increases with level.

For monsters, it is based on Challenge Rating.

CHARACTER PROGRESSION

Levels 1–4 → +2

Levels 5–8 → +3

Levels 9–12 → +4

Levels 13–16 → +5

Levels 17–20 → +6

SKILL PROFICIENCY

Add Proficiency Bonus to Ability Checks involving a skill in which you are proficient.

SAVING THROW PROFICIENCY

Add Proficiency Bonus to saves using an ability in which you have Saving Throw proficiency.

WEAPON PROFICIENCY

Add Proficiency Bonus to Attack Rolls made with weapons in which you are proficient.

TOOL PROFICIENCY

Add Proficiency Bonus to an Ability Check that uses a tool in which you are proficient.

If the relevant skill and tool proficiencies both apply:

YOU ALSO HAVE ADVANTAGE

 

THE BONUS DOESN'T STACK

Your Proficiency Bonus can't normally be added to the same roll or number more than once.

EXPERTISE

Expertise doubles your Proficiency Bonus for Ability Checks using the skill proficiency in which you have Expertise.

You must already be proficient in that skill, and you can't gain Expertise in the same skill proficiency more than once.

NEXT LESSON

LESSON 10 — ACTIONS: ATTACK, DASH, DISENGAGE, DODGE, HELP, HIDE, INFLUENCE, MAGIC, READY, SEARCH, STUDY, AND UTILIZE

You now understand the core mathematical systems behind D20 Tests.

Next, we move into one of the most practical parts of the game:

WHAT CAN YOUR CHARACTER ACTUALLY DO?

Lesson 10 will cover all twelve main actions in the SRD:

Attack

Dash

Disengage

Dodge

Help

Hide

Influence

Magic

Ready

Search

Study

Utilize

We will explain what each action does, when it is used, which rolls may be involved, and how these actions connect to exploration, social interaction, and combat.

SRD 5.2.1 ATTRIBUTION

This work includes material from the System Reference Document 5.2.1 (“SRD 5.2.1”) by Wizards of the Coast LLC, available at https://www.dndbeyond.com/srd. The SRD 5.2.1 is licensed under the Creative Commons Attribution 4.0 International License, available at https://creativecommons.org/licenses/by/4.0/legalcode.