How to Calculate & Increase Attack Bonuses in Dungeons & Dragons

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A guide to attack bonuses for every weapon and PC type

Co-authored by Legends of Avantris and Glenn Carreau

Last Updated: December 15, 2024 Fact Checked

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What is an attack bonus?

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Calculating Attack Bonuses

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Spellcasting Attack Bonuses

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Increasing Attack Bonuses

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Are you preparing for an exciting battle in your D&D campaign or equipping a new weapon on your player character (PC)? If so, you may need to calculate your PC’s attack bonus. In D&D 5e, a character’s attack bonus is the value added to a d20 roll when you make attacks against enemies. Thus, along with the d20 roll, your PC’s attack bonus determines their chances of making successful attacks! Keep reading for a complete guide to calculating your PC’s attack bonus in D&D 5e, complete with formulas for melee, ranged, and finesse weapons, as well as spells.

Things You Should Know

The basic formula to calculate your PC’s attack bonus is Ability Modifier + Proficiency Bonus + Enchanted Item Bonus + Class Features.
Use your PC’s Strength (STR) modifier to calculate their attack bonus with melee weapons and their Dexterity (DEX) bonus while using ranged weapons.
Calculate your PC’s spell attack bonus using their spellcasting ability modifier (which is either Intelligence, Charisma, or Wisdom, depending on their class).

Section 1 of 4:

What is an attack bonus?

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An attack bonus is the value added to a d20 roll when making attacks. In D&D 5e, targeting an enemy with a weapon attack or spell requires you to make an attack roll, which means rolling 1d20 and adding your PC’s attack bonus. That’s why it’s important to know how to calculate your PC’s attack bonus; it determines your character’s chances of successfully attacking enemies in combat.^{[1]
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- Attack bonuses rely on two major factors: your PC’s ability score modifiers and proficiency bonus.
- Ability score modifiers are added to attack rolls, saving throws, and ability checks; they directly affect your character’s skill in a particular ability. PCs have 6 ability scores in D&D, each with an associated ability modifier.
- A proficiency bonus is the value added to ability checks, attack rolls, and saving throws your PC is considered proficient in (something they specialize in or have extra training in).

Section 2 of 4:

How to Calculate an Attack Bonus

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Default formula The basic attack bonus formula is: Ability Modifier + Proficiency + Enchanted Item Bonus + Class Features = Attack Bonus. That means taking the ability score modifier that applies to the weapon your PC is using and adding their proficiency bonus plus any relevant enchantment or class feature bonuses; the result is their total attack bonus. However, many variables can change that formula.^{[2]
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Research source} For example:
- The correct ability modifier changes based on your weapon type. Strength (STR) and Dexterity (DEX) are the most commonly used ability score modifiers for attack bonuses.
- Not all characters have enchanted items or class features to use. The basic formula for an attack bonus is Ability Modifier + Proficiency; you only need to worry about class features or items if you have them.
- For specific ability score modifiers and weapon types, see the next steps in this section.
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Melee weapons with proficiency The basic attack bonus formula for melee weapons your PC is proficient in is: Strength (STR) Modifier + Proficiency Bonus. In other words, all you need to do is add their STR modifier to their proficiency bonus, and that’s their attack bonus. However, remember your PC might have situational class features or enchanted items, which can also be added to their attack bonus.^{[3]
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- For example, say your PC is a fighter with a greatsword (a melee weapon), a +4 STR modifier, and a +2 proficiency bonus. That means their attack bonus would be +6 (4 + 2).
- Then, say your fighter PC found an enchanted +1 greatsword. That means the greatsword is magical and grants a +1 to all attack rolls. The new attack bonus would be +7 (4 + 2 + 1).
- Melee weapons are any weapons you can use to attack an enemy within 5 feet of you (like swords, maces, and clubs).
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Melee weapons with the finesse property When using melee weapons with the finesse property, the attack bonus formula is: Dexterity (DEX) Modifier + Proficiency Bonus. Finesse weapons are a little more flexible than regular melee weapons; they typically rely on your PC’s Dexterity modifier, but you can choose to keep using Strength (if you prefer).
- Finesse weapons are lighter and rely on precision and agility. This includes rapiers, daggers, scimitars, and shortswords.^{[4]
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- For example, say you equip your rogue PC with a rapier. If your PC has a +5 DEX modifier and a +3 proficiency bonus, their attack bonus would be +8 (5 + 3).
- Then, say a fellow PC used a class feature like Bardic Inspiration to give your rogue another +2 bonus to their attack roll. Their attack bonus would be +10 (5 + 3 + 2).
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Ranged weapons Attacks with ranged weapons always use your PC’s Dexterity modifier, so the formula is: Dexterity (DEX) Modifier + Proficiency Bonus. Ranged weapons include any weapons (like shortbows, longbows, crossbows, and darts) that can be used to attack at a distance.^{[5]
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- For example, if your ranger PC is wielding a longbow with a +3 DEX modifier and a +4 proficiency bonus, their attack bonus would be +7 (3 + 4)
- A +2 enchanted longbow would also give your PC a +2 bonus to attack rolls, bringing their attack bonus to +9 (3 + 4 + 2).
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Thrown weapons Thrown weapons use the same formula as melee weapons. So, the formula for most thrown weapons is Strength Modifier + Proficiency. However, if you’re throwing a finesse weapon, you can choose between your PC’s Dexterity or Strength modifiers. Generally, when you have options, the best choice is whichever ability modifier is higher.^{[6]
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- For example, if your PC throws a hand axe, the formula would be STR + Proficiency. If your PC throws a dagger (a finesse weapon), you can choose between DEX + Proficiency or STR + Proficiency.
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Weapons without proficiency When your character doesn’t have proficiency in the weapon they’re wielding, their attack bonus is simply their Strength (or Dexterity, depending on the weapon) modifier. Technically, your PC can equip a weapon they’re not proficient in, but because you can’t add their proficiency score to the total attack bonus, your PC is less likely to make successful attacks with such weapons.^{[7]
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- For example, if your PC is only proficient in simple weapons (like daggers, staffs, clubs, and hand axes) and you equip them with a longsword (classified as a martial weapon, not a simple weapon), they wouldn’t be proficient.
- Longswords rely on Strength (since they’re melee weapons without the finesse property). So, if your PC’s STR modifier is -1, their attack bonus with the longsword would also be -1, which isn’t ideal.

Section 3 of 4:

Calculating Spellcasting Attack Bonuses

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Spellcasters have a spellcasting attack bonus determined by their class. For spell attacks in D&D 5e, the formula for determining an attack bonus is: Spellcasting Modifier + Proficiency. Thankfully, spellcasters always have proficiency on spell attacks! Meanwhile, your PC’s spellcasting modifier is essentially the ability score modifier they use to cast spells—it’s always either Intelligence (INT), Wisdom (WIS), or Charisma (CHA).^{[8]
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Research source} For example:
- Wizards and artificers use their Intelligence (INT) modifier to cast spells. So, if your wizard PC’s INT modifier is +4 and their proficiency bonus is +4, their spell attack bonus is +8 (4 + 4).
- Clerics, druids, and rangers use their Wisdom (WIS) modifier to cast spells, so their spell attack bonus is: WIS modifier + Proficiency.
- Bards, warlocks, sorcerers and paladins use their Charisma (CHA) modifier to cast spells, making their spell attack bonus: CHA modifier + Proficiency.

Section 4 of 4:

How to Increase Attack Bonuses

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Boost your ability score modifier. The higher your PC’s ability score modifier gets, the higher their attack bonus will get, and a higher attack bonus increases their chance of successfully attacking enemies. First, choose an ability to increase based on your PC's weapon type—do they wield a Dexterity-based weapon (like a longbow) or a Strength-based weapon (like a longsword)? Then, focus on improving that ability modifier.^{[9]
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Research source} Ways to improve ability modifiers include:
- Ability Score Improvement. Periodically, you can give your PC an ability score improvement upon leveling up, increasing a single ability score by 2 (or 2 ability scores by 1).
- Feats. Some feats (optional abilities you can give your PC in place of ability score improvements) can increase a specific ability score. For example, the Athlete feat lets you choose between a +1 bonus to STR or DEX.
- Magic items. A few magic items can directly boost your PC’s ability scores. For example, the Manual of Quickness of Action and the Ioun Stone of Agility both provide DEX bonuses, and the Gauntlets of Ogre Power can raise your STR to 19.
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Level up to automatically increase your proficiency bonus. As your PC’s proficiency bonus increases, their attack bonus will also increase. Luckily, you don’t need to do anything special to boost their proficiency bonus; it’ll automatically go up as your PC gains levels. So, just keep playing D&D and stay on top of leveling up your character! Beyond that, ensure your character is proficient with whatever weapon they have equipped (so they’ll get a proficiency bonus in the first place).^{[10]
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- Proficiency modifiers change by level. As your character advances in level, their modifier changes accordingly:
  - Levels 1 to 4: +2
  - Levels 5 to 8: +3
  - Levels 9 to 12: +4
  - Levels 13 to 16: +5
  - Levels 17 to 20: +6
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Equip enchanted weapons with built-in attack bonuses. It’s common to find enchanted weapons as you adventure (and find loot) in D&D. In 5e, enchanted weapons typically come with an attack and damage bonus ranging from +1 to +3 (the higher the bonus, the rarer the weapon). Keep an eye out for enchanted weapons your character is proficient in, and equip them when you find them!^{[11]
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- Some enchanted items only have an attack and damage bonus (like a Longsword +2 or a Greataxe +3), while others have unique names and additional perks.
- For example, a Mace of Smiting might be a good choice if you play a cleric or paladin. It comes with a +1 bonus to attack and damage rolls and deals extra damage on critical hits.
- Spellcasters can also find magic items with attack bonuses. For example, the Wand of the War Mage grants a +3 bonus to spell attack rolls for all spellcasting classes.
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Use class features that can boost your attack bonus. Unfortunately, not many class features can directly improve your attack bonus, but there are a few to remember! Bardic Inspiration (a feature available to all bard PCs) can grant bonuses to attack rolls, saving throws, and ability checks, for example. At the same time, Battle Master fighters can learn Maneuvers and add Superiority Die to their attack rolls, thus increasing their attack bonus.^{[12]
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Research source} Other features include:
- Channel Divinity. War domain clerics and Oath of Devotion paladins can use their Channel Divinity feature to get a significant attack bonus increase.
- Archery Fighting Style. This style (available to fighters and rangers) grants a flat +2 attack bonus when your PC uses ranged weapons.
- Bless. This 1st-level spell grants a 1d4 bonus to attack rolls and saving throws. It’s available to cleric and paladin PCs.
- Elemental Weapon. This 3rd-level spell is available to paladins, letting them turn a nonmagical weapon into a magical one with a +1 attack bonus.
- Magic Weapon. Paladins and wizards have access to this 2nd-level spell that turns nonmagical weapons temporarily magical, with a +1 attack bonus.
- Bend Luck. Wild Magic sorcerers get the Bend Luck feature, which lets them add 1d4 to an ally’s attack, saving throw, or ability check bonus.