Last Updated on January 22, 2023
If you’re a new player, working out exactly what a proficiency bonus is, how it works, and when to apply it can feel like a whole lot of unnecessary extra mathematics – especially if you’re already trying to figure out how to play your first character.
While proficiency bonuses can feel a little complex at first (I’ve run D&D for enough first time players to be sure that nothing makes people’s eyes glaze over faster than explaining that their spellcasting modifier at 1st level is 8 plus their spellcasting ability modifier plus 2 – “but where does the 2 come from?
Why isn’t it just 10 plus my Charisma?”) but once you have a handle on it, I swear to Bahamut that it’s actually a really neat piece of game design.
All characters (and monsters, actually) have a proficiency bonus in Dungeons & Dragons 5e – the first edition to use this rule. As your character grows in levels, your proficiency bonus increases, making you more likely to succeed on skill checks, attack rolls, and saving throws where it applies.
Some classes, like the rogue and the bard, get to enhance the benefits granted by their proficiency bonus even further through abilities like Expertise and Jack of All Trades.
In this guide, we’re going to break down exactly what a proficiency bonus is, how it works, when to use it, when not to use it, and how it interacts with special class features like Expertise and Jack of All Trades.
What is a Proficiency Bonus?
All characters have a proficiency bonus determined by their level. This flat bonus is applied to all d20 rolls made in situations where your character is “proficient”. For example if you are proficient in lock picking, you apply the proficiency bonus when attempting to pick a lock.
Think of it like a flat Ability Score Modifier that only applies in specific situations. A character with an Intelligence modifier of +3 adds that bonus to any roll that relies on them using their intellect.
If that character tries to decipher a book of magical runes, however, and is also proficient in Intelligence (Arcana), they get to add their proficiency bonus on top of their Intelligence modifier. That number is then added to the result of the base roll they made with a d20.
Depending on the areas in which your character is proficient, you can add your proficiency bonus to:
- Attack rolls using weapons you’re proficient with
- Attack rolls with spells you cast
- Ability checks using skills you’re proficient in
- Ability checks using tools you’re proficient with
- Saving throws you’re proficient in
- Saving throw DCs for spells you cast
All characters start out with a proficiency bonus of 2, which increases as they level up.
|Character Level||Proficiency Bonus|
Your proficiency bonus also determines how often some class abilities and spells can be activated between rests.
For example, the Gift of the Chromatic Dragon Feat allows you to give yourself resistance to either acid, cold, fire, lightning, or poison damage a number of times equal to your proficiency bonus per long rest.
A 1st level character would be able to resist one of the above damage types twice per long rest. A 20th-level character, on the other hand, would be able to activate this Feat a full six times per long rest.
Am I Proficient With That?
As well as adding a bonus to certain checks, saves, and attacks, whether your character is proficient with a piece of equipment or magic item can affect how useful they’re going to be with it.
Characters’ proficiency with different types of Weapon, Armor, and Tools (which can also include gaming sets and musical instruments) are usually laid out by their class, but can also be affected by their race (elves tend to get longbow proficiency, and dwarves are good with hammers), and background (the Criminal background gives you proficiency with Thieves’ Tools, for example).
Weapon Proficiency lets you add your proficiency bonus to attack rolls made with that weapon.
Armor Proficiency affects whether you can gain the benefits of light, medium, or heavy armor and shields. Anyone can put on a suit of armor or pick up a shield, but if you aren’t proficient in its armor type, you suffer disadvantage on any ability check, saving throw, or attack roll that relies on Strength or Dexterity, and you can’t cast Spells.
Tool Proficiency not only determines whether you add your proficiency bonus to checks made using a specific type of tool (Thieves’ Tools, Mason’s Tools) or kit (Disguise Kit, Brewers Supplies, etc.), but whether or not you can even attempt to use the piece of equipment (which also includes musical instruments and gaming sets; it makes sense given how many times I’ve sat down at a piano and tried to just “give it my best shot”, or the first time I booted up Dwarf Fortress without reading a starter’s guide) at all.
How Do I Use My Proficiency Bonus?
Even when you know your proficiency bonus and which skills, saving throws, and equipment types it applies to, calculating exactly how it affects your dice rolls can still feel a little overwhelming.
When you create your character (or when you level up), it’s important to make sure you apply your proficiency bonuses to all the relevant sections of your character sheet. Using an online character manager like D&D Beyond does a lot of work to streamline this process.
Can I Stack My Proficiency Bonus?
It’s important to note that you can only apply your proficiency bonus to a dice roll once. Even if two different rules say that you can add your proficiency bonus to a Wisdom saving throw, for example, you still only apply the bonus once.
Features like Expertise and Jack of All Trades can also multiply or half your proficiency bonus when making a roll. In cases where multiple rules suggest that you would multiply or divide your proficiency bonus more than once, you only multiply or divide it once.
Lastly, if a feature allows you to multiply your proficiency bonus when making a check with which you are not proficiency, you still do not get to add your proficiency bonus to that check. Multiplying 0 by any number is still 0.
Your class, race, background, and some Feats all have the potential to give you proficiency in certain skills. When making a skill check where your proficiency applies, in order to calculate the result, add the result of your d20 roll to your ability modifier and proficiency bonus.
For example, a 5th level fighter with Strength 18 and proficiency in Strength (Athletics) is trying to climb a wall. The player rolls 11 (d20 base roll) + 4 (Strength modifier) + 3 (proficiency bonus), for a total 18 to try and beat the DC of 16. Success! Note that, if the fighter wasn’t proficient in the Strength (Athletics) skill, the result of the roll would have been 15: a failure.
Your class (as well as some Feats like Resilient) determine the abilities where you have saving throw proficiency. When you make a saving throw with an ability score with which you are proficient, you add your proficiency bonus to your ability modifier and the result of the base d20 roll – like a skill check.
If your character has access to spellcasting, your proficiency bonus is used to determine both your Spell Save DC (the number creatures have to beat in order to resist, avoid or weaken your magic’s effects) and Spell Attack Bonus (the number you add to your base d20 roll when making a Spell Attack against one or more targets).
Your Spell Save DC = 8 + Your Spellcasting Ability Modifier + Proficiency Bonus
Your Spell Attack Bonus = Your Spellcasting Ability Modifier + Proficiency Bonus
For example, a 1st level Wizard with an Intelligence score of 16 (+3) has a Spell Save DC of 13 (8 + 3 + 2) and a Spell Attack Bonus of +5 (3 + 2).
When you make a weapon attack with a type of weapon your character is proficient with, you add your proficiency bonus to the attack roll.
For example, a 1st level Fighter (who is proficient with all weapons and armor) with a Strength of 16 (+3) attacks a goblin with her longsword. The player running the Fighter rolls a 10 (base d20 roll) + 3 (Strength) + 2 for a total of 15, hitting the goblin’s armor class.
A 1st level Wizard, on the other hand, who is only proficient with simple weapons and also inexplicably has 16 Strength, uses the same longsword to attack the same goblin.
Even though the Wizard rolled higher (11), they cannot add their proficiency bonus to an attack roll with a weapon they’re not proficient with, meaning the result is a 14 (11 + 3): a miss.
When Don’t I Use My Proficiency Bonus?
As a good rule of thumb, you only ever add your proficiency bonus to a roll made with a d20. Damage rolls, healing rolls, and other rolls made with other types of dice are not affected by your proficiency bonus.
There are some exceptions, like the Hexblade Warlock’s curse ability (which lets you add your proficiency bonus to your damage rolls against a single target) but largely your proficiency bonus is exclusively for checks, saves, and attack rolls.
Also, remember that you only ever apply your proficiency bonus to a roll once. If your character has two features that give them proficiency in a skill, they only ever apply a single instance of their bonus.
What Are The Most Common Skills To Have Proficiency In?
The skills your character is proficient in are largely determined by your class and role within the party, as well as which of your ability scores is highest.
A wizard with an 18 (+4) in Intelligence and an 8 (-2) in Strength is unlikely to get much use out of Strength (Athletics) proficiency – although you could argue that this means they no longer roll with a -2 modifier, so I guess there’s a case to be made.
However, it’s more likely that characters choose skill proficiencies that further enhance the things their class is already good at. Wizards tend towards being proficient in Arcana, History, and Nature; Bards (with their typically high Charisma scores and socially-focused skillset) tend towards proficiency in Persuasion, Deception, and even Intimidation.
There is no one “best” skill in D&D 5e, but being able to add your proficiency bonus to Wisdom (Perception) checks is going to pay dividends for just about every class, as a good Perception roll can be the difference between spotting a useful clue or a hidden door, and getting ambushed by goblins in a dark hallway.
Rogues are all about highly specific knowledge that centers around the various tricks of their trade: namely, being sneaky, stabby, and sticky-fingered. Mechanically, the rogue’s propensity for honing their skills to a razor’s edge is expressed through their Expertise class feature.
At 1st level, rogues choose two skill proficiencies, or one skill proficiency and their proficiency with thieves’ tools. These are their areas of Expertise.
Whenever a rogue makes an ability check that uses one of their chosen proficiencies, they double their proficiency bonus.
A 4th level rogue with Expertise in Dexterity (Sleight of Hand) and a Dexterity of 18 (+4) gets a total bonus of +8 to Dexterity (Sleight of Hand) checks. At 20th level, that rogue (who now has a Dexterity of 20) gets a bonus of +17 – a Dexterity modifier of +5 + 12 (Proficiency bonus 6 x 2) to the same check.
At 6th level, rogues get to choose an additional two skills (or Thieves’ Tools if they haven’t chosen them already) in which they have Expertise.
Bards also gain access to Expertise, although they benefit from the feature later than rogues. Bards gain expertise in two skill proficiencies at 3rd level and may select another two when they reach 10th level.
Jack of All Trades
Whereas rogues focus all of their talents on being frighteningly good at a few things, bards excel at being able to do a little bit of everything (and then, a little later, decide to get really, really good at a few things as well; bards are all that one friend who’s on his third bachelor’s degree in his mid-thirties and later decides to get a PhD in Forensic Science when he’s 40 just for kicks).
Starting at 2nd level, a bard’s Jack of All Trades feature means that they can add half of their proficiency bonus (rounded down) to any ability check that isn’t already affected by their proficiency bonus.
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I played my first tabletop RPG (Pathfinder 1e, specifically) in college. I rocked up late to the first session with an unread rulebook and a human bard called Nick Jugger. It was a rocky start but I had a blast and now, the better part of a decade later, I play, write, and write about tabletop RPGs (mostly 5e, but also PBtA, Forged in the Dark and OSR) games for a living, which is wild.