Attack Bonus (AB) in DnD 5E explained

Increase your combat prowess by understanding the Attack Bonus 5E. Enhance your chances of striking true.

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When you make an attack in Dungeons & Dragons 5E, you roll a D20, adding your Attack Bonus (AB) to determine the total. So how do you assess your Attack Bonus (AB)?

Weapon Attack Bonus

Melee weapon attacks will use your Str modifier, and you may instead use your Dex modifier if you’re using a weapon with the Finesse property.

Ranged weapon attacks will use your Dex modifier. If you’re attacking with a thrown weapon, you use the same modifier as you would to make a melee attack. For example, a handaxe will use Str when thrown, but a dagger can use either Str or Dex because a dagger is a Finesse weapon.

If you are proficient with the weapon you are using, you add your proficiency bonus to your ability score mod. A Fighter making a melee attack with a longsword would use the following to determine their Attack Bonus:

Str Mod + Proficiency = Attack Bonus

A Ranger making a ranged attack with a longbow would use the following to determine their Attack Bonus:

Dex Mod + Proficiency = Attack Bonus

Note: Some class features allow you to use alternative stats for weapon attacks; these include the Monk’s Martial Arts, the Hexblade Warlock patron’s Hex Warrior, and the Battle Smith Artificer’s Battle Ready. The Shillelagh cantrip is also an exception to these general rules.

Spell Attack Bonus

Spell attacks are more straightforward than their weapon counterparts, as you’re always proficient in a spell you are casting:

Spellcasting Mod + Proficiency = Spell Attack Bonus

The ability score that you use for your spellcasting modifier is dependent on where the spell you are casting came from. This is straightforward for single classed spell casters, but if you are a multiclassed spellcaster (and those classes use different spellcasting stats), you need to know which stat the spell you are casting uses.

For example, a Wizard has the Firebolt cantrip and then takes a one level dip in Sorcerer and chooses Shocking Grasp. Firebolt is a Wizard spell; it uses the PC’s Int as the spellcasting mod, but Shocking Grasp will use Cha because it is a Sorcerer spell. This also applies to spells gained from feats and races. They may have different casting stats, so it’s always advisable to double-check and note which spells use other stats.

How can you increase your Attack Bonus?

Besides increasing your Attack Bonus by increasing your primary stat and leveling up to gain a higher proficiency bonus, there are other ways to increase your Attack Bonus. Here are some examples:

ArcheryFighting StyleAttacks made with ranged weapons2
Bless1st level spellAll attacks+1d4
Favored by the GodsDivine Soul abilityAny attack that misses+2d4
Guided StrikeChannel Divinity (War Domain and Oath of Conquest)Any attack10
Magic WeaponMagic ItemAttacks with that weapon+1,+2, or +3 
Magic FocusMagic ItemSpells cast through that focus6
Saving FaceHobgoblin AbilityAn attack that missesUp to +5

There we have it. It’s not difficult to work out your Attack Bonus when you know how and in practice you’ll be able to work it out once and make a note of it as it won’t increase that often. Now that you’re informed on Attack Bonuses and some ways to increase them, go out and hit that bullseye, well, assuming you don’t roll a natural one of course!

Expert Editor-in-Chief