How to calculate Proficiency Bonus (PB) in DnD 5E

Your guide to calculating Proficiency Bonus in 5E for skill checks and attacks.

© Dice Cove

Sometimes, you know a little bit of everything (Jack of All Trades), others you can do something well (Proficiency), and very rarely, you’re really good at something (Expertise). There’s a surprising amount that Proficiency Bonus (PB) impacts, and it even affects some features that Tasha’s Cauldron of Everything has added in. And because of the Ability Score Limits when Rolling Stats or getting an Ability Score Improvement, Proficiency Bonus (usually) makes up most of the bonuses to your rolls once you hit high levels (if you even get there), and thus is very powerful when used right. It is the difference between the apprentice, and the master, and you can’t get there overnight (except with maybe time loops, and ridiculous dungeons).

The formula for the Proficiency Bonus is {2 + (Total Level-1)/4}Rounded Down or 1 + (total level/4)Rounded up, both formulas will give the same results. Not that you even need this formula (unless homebrewing beyond Level 20, or making a program) because the values are all printed on each class table. Note I used Total Level instead of Level. This is because your level in ALL CLASSES is used for this calculation, so you can actually multiclass in everything and still have a high Proficiency Bonus for everything that uses it.

Quick side note: Monsters also have a Proficiency Bonus which until Tasha’s, haven’t been added to stat blocks, but are pre-added to all rolls that use them. The calculations for them are based on the same formula, but use CR instead of Level.

Now there’s a lot of stuff that adds Proficiency to rolls. Spells use it for Spell Attack Bonus, and Saving Throw DC (maybe I’ll write an article on Spellcasting Explained someday), You use it for Your class’s Saving Throw Proficiencies, your Proficient/Expertise/Jack of all Trades Skill checks from Class and Background, Attack rolls for Proficient Bonuses, and uses for some of the new class features since Tasha’s Cauldron of Everything.

Of course, there’s an alternative to Proficiency Bonus called, Proficiency Dice, which follows the same progression, except it starts as 1d4, then goes to 1d6, 1d8, 1d10, and eventually 1d12. It’s a lot more chaotic and time-consuming unless you’re playing with a virtual dice roller that adds all that stuff for you, but it’s much more chaotic, but is also has a lot more chance to come in clutch where your regular Proficiency Bonus would fail you, making Saving Throws really easy, or really hard!

If you really want to, you could actually homebrew your own version (as everybody can), and I have 2 ideas you can try out at your game table:

  • Have a number of Fate Dice (d6 with 2 Blank, 2 Success, 2 Failure) equal to your standard Proficiency Bonus, and roll them. Each Success is +1 to your Proficiency Bonus, each Failure is -1, if you get more than half Success, get advantage on your next roll, and if more than half is Failure, get disadvantage on your next roll
  • Pull out any 7-Q from any standard playing card deck, and use that as a Proficiency Deck. When you would use your Proficiency Bonus, you can choose to either use your Proficiency Bonus as normal, or draw a number of cards equal to what your Standard Proficiency Bonus would be, blindly pick from them, and use the value of that card as your Proficiency Bonus. If you draw a diamond, you double that Bonus, if you draw a spade, half that Bonus. If you draw a red king, the roll succeeds, but if you draw a black king, the roll fails.

These haven’t been playtested at all as I came up with them on the spot, but you’re welcome to try them and let me know what you think of them. But now that the ground is no longer unfamiliar terrain, you can add your Proficiency Bonus when playing your games. And perhaps some of the other articles we have might give you expertise! Have fun out there!