What is an Attack Bonus in D&D 5e?This post may contain affiliate links. If you buy something we may get a small commission at no extra cost to you. (Learn more).
An Attack Bonus is a number that’s added to a D20 roll when you make an attack in D&D 5e. There are several types of attacks that have an attack bonus – melee attacks, ranged attacks, spell attacks, and thrown weapon attacks.
And a character’s attack bonus may differ for some of these, or all of these.
The number for an attack bonus should include a positive (+) or negative (-) sign, although hopefully you don’t have a negative attack bonus!
Here I’ll go through how to calculate your attack bonus for various types of attacks so you can understand how it works in a “real world” scenario.
But if you look in the middle of the first page of a 5e character sheet, you’ll see a section called “Attacks & Spellcasting” that has a space for the Attack Bonus.
Depending on which version of the sheet you’re using, it may read “ATK BONUS” or “Attack Bonus.” In DNDBeyond it reads “HIT/DC.”
The exact wording doesn’t matter, because they all mean the same thing.
Calculating an Attack Bonus
Now let’s look at how you typically calculate the attack bonus for a specific attack.
For melee attacks using a weapon you’re proficient with, the attack bonus is the strength modifier plus the proficiency bonus. If you use a weapon that you are not proficient with, the attack bonus is just the strength modifier.
For melee attacks using a weapon with the finesse property, you can use the dexterity modifier instead of the strength modifier if you wish. As before, you also include your proficiency bonus if you’re using a weapon you’re proficient with.
For ranged attacks, the attack bonus always uses the dexterity modifier. As before, you should add the proficiency bonus if you’re proficient with the weapon.
For thrown weapons, the attack bonus is calculated just as with melee weapons. So throwing a hand axe always uses strength, but throwing a dagger can use strength or dexterity because it’s a finesse weapon.
For spell attacks, the attack bonus is the spellcasting modifier plus the proficiency bonus. Spellcasters always have proficiency in making spell attacks.
Examples & Scenarios
As an example let’s look at Rafi, a level 5 Arcane Trickster with Dexterity 18 (+4), Strength 14 (+2) and Intelligence 16 (+3).
As a level 5 character, Rafi has a proficiency bonus of +3.
As an Arcane Trickster, she uses Intelligence to cast spells.
She has proficiency in simple weapons but not in most martial weapons.
When wielding or throwing a dagger, which is a simple finesse weapon, Rafi has a +7 attack bonus (+4 from dex and +3 from her proficiency bonus). She uses this same bonus for swinging or throwing the dagger. Rafi could use Str instead of Dex, but that wouldn’t make much sense because the attack bonus would only be +5.
When wielding a spear, which is not a finesse weapon but is a simple weapon, Rafi has a +5 attack bonus (+2 from Str and +3 from her proficiency bonus). Rafi uses this same bonus for stabbing or throwing the spear.
When wielding a great sword, which is a martial weapon, Rafi has a +2 attack bonus (+2 from Str, but no proficiency bonus).
When shooting a light crossbow, which is a simple ranged weapon, Rafi has a +7 attack bonus (+4 from dex and +3 from her proficiency bonus).
When shooting a heavy crossbow, which is a martial ranged weapon, Rafi has a +4 attack bonus (+4 from dex, but no proficiency bonus).
When casting a spell that requires a spell attack, Rafi has a +5 spell attack bonus (+2 from Int and +3 from her proficiency bonus).
So if Rafi were to cast the spell booming blade and attack with her dagger, she would have a +7 attack bonus because that particular spell asks her to make a melee attack and not a spell attack.
As you can see, it can take work to figure out the different attack bonuses.
Fortunately it’s usually not too difficult to adjust your attack bonus as you level up.
When your proficiency bonus goes up (levels 5, 9, 13 and 17), your attack bonuses will usually increase. If you take an ASI, your attack bonus might increase. Also using a magic weapon or learning certain fighting styles might alter your attack bonus.
However, there aren’t many spells, class features, or feats that affect your attack bonus.
The designers of 5e did this intentionally.
They tried not to overcomplicate the system with lots of little bonuses. That’s a good thing, in my opinion.
It’s much more fun to roll dice and role-play than it is to spend a lot of time doing math in your head!