Attack Bonus 5e: How to Calculate

Attack Bonuses increase the hurt on your enemies. Learn how Attack Bonuses work in DnD 5e to harness all your power. 

Attack Bonuses in 5e depend on:

1. Your ability modifier (such as +2 in STR or +3 in DEX)
2. Whether you have proficiency in the weapon you’re using

Ability modifiers depend on your ability score (how high that particular stat is). Whether you get a proficiency bonus depends on if you’re proficient in the weapon you’re using. The amount of the proficiency bonus depends on your level. 

The ability modifier for a melee weapon attack is Strength. The ability modifier for a ranged weapon attack is Dexterity. Weapons with Finesse can use either Strength or Dexterity. Thrown melee weapons use Strength, and Thrown ranged weapons use Dexterity. Thrown weapons with Finesse can use either Strength or Dexterity. If applicable, spells use the Spellcasting ability modifier. 

When you choose “Attack” for your action, you have to do two rolls, one for hit and one for damage if you succeed on the hit. Your hit roll uses both your ability modifier and proficiency modifier as attack bonuses. Your potential damage roll uses only your ability modifier. 

Example of How Attack Bonuses Work

Say you’re a beefy level 5 Barbarian with a Strength of 14 using a simple Shortsword, which you are proficient in. At level 5, proficiency gets you a +3 bonus. Your Shortsword is a melee weapon, so it will add any ability modifier for Strength. Your Strength is 14, so that gives you an additional +2 ability bonus.

Every enemy (and player) in DnD 5e has an AC, or Armor Class. Your hit roll + attack bonuses have to be higher than the AC to hit.

The Golem you’re facing has an AC of 14. You roll a measly 10 to hit, and wince…but wait! With your proficiency bonus of +3 and your ability bonus of +2, you juuust squeak out a hit. Hurray!

Now you roll for 1d6 for damage, blowing on it for luck (every weapon uses a certain number of certain dice, Shortsword uses 1d6). You get lucky and get a 6. With your Strength ability modifier of +2, that means you do smash the giant for solid 8 damage!

Do Spellcasters get Attack Bonuses?

Yep! Instead of an ability modifier, Spellcasters use their Spellcasting modifier. Only for some spells, though.

Some spells require the caster to make an attack roll to see if the spell effect hits the intended target. Your attack bonus with a spell attack is your Spellcasting ability modifier + your Proficiency bonus. All spellcasters are proficient in spells! So you just have to reference the Proficiency bonus for your level. This includes spells from magic items.

How to Calculate Attack Bonuses

Here’s how Proficiency bonuses scale to level for Attack bonuses:

Level	Proficiency Bonus
1	+2
2	+2
3	+2
4	+2
5	+3
6	+3
7	+3
8	+3
9	+4
10	+4
11	+4
12	+4
13	+5
14	+5
15	+5
16	+5
17	+6
18	+6
19	+6
20	+6

Here’s how Ability Modifiers scale to ability scores for Attack Bonuses:

Ability Score	Modifier
1	−5
2–3	−4
4–5	−3
6–7	−2
8–9	−1
10–11	+0
12–13	+1
14–15	+2
16–17	+3
18–19	+4
20–21	+5
22–23	+6
24–25	+7
26–27	+8
28–29	+9
30	+10

Ability Modifiers affect almost every Attack roll, ability check, and saving throw, so keep them handy! You can also cut your ability score in half, and divide by 2 (rounding down) to find your ability modifier.

Summary of Attack Bonuses in Dnd 5e: 

To calculate if you hit a target and bypass their AC:

= 1d20 + ability modifier + proficiency bonus (if proficient).

To roll damage upon bypassing a target’s AC:

= Weapon dmg (dice) + ability modifier.

Melee weapon ability modifier	Strength
Ranged weapon ability modifier	Dexterity
Finesse weapon ability modifier	Strength OR Dexterity, you choose
Thrown weapon ability modifier	Strength (Melee), Dexterity (Ranged), Your choice STR or DEX (Finesse)
Spells that require attack rolls	Spellcasting modifier

Bonus tip: Don’t forget to narrate all your attacks!