How to Figure the Dice and Bonuses for Attack Rolls and Damage Rolls?

In D&D 5e, an attack roll determines whether the attack you made on the opponent will hit or miss your opponent, whereas a damage roll calculates the amount of damage you deal with an attack. Many new D&D players often find it tough to determine the type of modifiers they should add to figure out their attack and damage roll bonus.  

This article will help you to figure out the type of modifiers added to the attack roll and damage roll bonus. It will also guide you to determine the number of bonus points you get from using different weapons and spells to gain the maximum attack and damage roll bonus. 

How Is the Attack and Damage Roll Bonus Calculated?

According to the Player’s Handbook (PHB page 194), you can calculate your attack roll by rolling a 1d20 dice and adding your proficiency and Dex modifier. However, you only need the Dexterity modifier to calculate your damage roll bonus, roll a 1d8 dice and add your Dexterity modifier. But, there is a more precise method to calculate the attack and damage roll bonus. Let us see it below:

Calculating Attack Roll Bonus: 

According to the rules mentioned in Chapter 9: Combat of the D&D 5e‘s PHB, page 189, you should add ability modifiers, proficiency bonus, weapons, and other effects to calculate the attack roll bonus.

Confused Between DEM, DTM and DSM !

Ability Modifier

  • For attack roll spells, the ability modifier is your spellcasting ability, which can be Intelligence, Wisdom, or Charisma. However, it can be the strength modifier for Melee weapons and a dexterity modifier for many ranged weapons.
  • The Finesse property allows you to choose between Dexterity or Strength while making an attack, and you can use the same modifier for the Damage roll. If you follow the rules of the core game, then this property applies only to Melee Weapons. 
  • According to page 55 of  Xanathar’s Guide to Everything (XGtE), a Hexblade uses Charisma instead of Strength or Dexterity for their weapon attack and damage rolls if they use a weapon that matches the requirements of their Patron. 

Your Proficiency Bonus

  • If you have proficiency in any weapon, you get a proficiency bonus. The Martial classes like Fighters, Barbarians, or Paladins gain proficiency bonuses by using any weapon in the game. However, consult the proficiency bonus chart of other classes to determine their proficiency bonus.
  • No class gain proficiencies by using “Exotic Weapons.” Players can attain the proficiency bonus from these weapons only if they gain proficiency through other means or weapons. The core game does not contain any Exotic Weapons. 
  • To gain the proficiency bonus by using spells, you need proficiency in spellcasting spells. 

Special Modifiers on the Weapons

Magic weapons, such as the A +1 weapons listed on page 213 of the Dungeon Master’s Guide (DMG), offer attack and damage roll bonuses. A + 1 weapon grants a +1 bonus to attack and damage rolls.

Buffs or Other Effects

The Spell Bless mentioned on page 219 of the PHB adds a d4 roll to any attack roll made by the target. 

If a level 5 Fighter wields a +1 Rapier (that has Finesse property) and has a Strength score of 16 and dexterity of 18 would gain the following bonus for their Attack Roll:

Ability Modifier: The player would gain +3 if they use the Strength modifier, or they could gain +4 by using the dexterity modifier. 

Proficiency Bonus: Fighters gain proficiency in Rapiers, so a level 5 character or Rapier would gain a +3. 

Magic Weapons: Magic weapons gain +1 attack roll.

Total attack roll bonus: Your overall attack roll bonus would be +7 for Strength and +8 for Dexterity.

Calculating Damage Roll Bonus:

Add the weapons damage dice (1d8) + the ability modifier associated with the attack to calculate the damage roll bonus in the D&D game. Here is the precise method for calculating the damage roll bonus:

Ability Modifier

  • The ability modifier would be Strength for Melee weapons, Dexterity for Ranged weapons, and it could be either Strength or Dexterity for weapons possessed of the Finesse property. 
  • Spells do not benefit from this damage roll unless the character has a particular trait that permits them to profit from it. The Evocation Wizard (PHB, page 117 ), the Agonizing Blast Warlock feature (PHB, page 110), or the Green Flame Blade (Sword Coast Adventure’s Guide, page 143) expressly says that you are allowed to add your spellcasting or ability modifier to the damage roll produced by these spells. 

No Proficiency Bonus

The players should never add their Proficiency Bonus to their damage rolls, even if they have proficiency in those weapons or spells. Only some exception classes like Necromancy Wizards allow their summons (specifically those created by necromancy magic) to add the wizard’s proficiency bonus to their damage rolls. 

Special Modifiers

Some magic weapons grant bonuses to the damage roll, attack roll, or sometimes to both the rolls. A +1 Weapon mentioned in the Dungeon Master’s Guide, page 213, confers a +1 bonus to both damage and attack rolls. 

Buffs or Other Effects

A spell Divine Favor [PHB, page 234] allows the target to add 1d4 Radiant damage to their damage rolls produced by weapon attacks. 

So, if a Fighter class uses the Dueling Fighting Style (which confers them a +2 bonus to damage rolls when a character does not wield more than one weapon and only wields that weapon in one hand)), the damage roll bonus of that character would be:

Ability Modifier: It would be +3 if they use a Strength modifier, or it could be +4 if they use the Dexterity modifier.

Proficiency Bonus: 0 since it does not contribute to damage rolls.

Magic Weapons: +1

Buffs or Other Effects: The Dueling Fighting Style adds +2 to damage rolls for one-handed weapons if a character does not wield another weapon. 

Note: Proficiency is explicitly not added while calculating damage roll bonus unless some features expressly say to add it to the damage roll, such as Necromancy Wizards. Additionally, Fighter characters with Finesse weapons may use any modifier, though they have to use the same modifier for both attack and defence. So, they could not choose to use the Strength modifier for the attack roll and the Dexterity modifier for the Damage roll. 

Now, let us consider a few examples for calculating attack and damage roll for wizards and rogues:

A level 5 Wizard casting Fire Bolt, with an Intelligence of 18:

Attack Roll: The Attack roll would be 1d20 + 4 (Intelligence) + 3 (Proficiency). Total would be = 1d20 + 7.

Damage Roll: The damage roll for casting Firebolt would be 2d10.  

A level 10 Evocation Wizards casting Fire Bolt with Intelligence of 20

Attack Roll: The Attack roll would be 1d20 + 5 (Intelligence) + 4 (Proficiency). Total would be = 1d20 + 9.

Damage Roll: The damage roll would be 2d10 (for casting Firebolt) + 5 (Intelligence, Empowered Evocation [PHB, 117]). 

A level 13 Rogue wielding a Longsword with 20 Dexterity modifier and 10 Strength modifier:

Attack Roll: The Attack roll would be 1d20 + 0 (Strength) + 0 (Non-Proficiency). Total would be = 1d20.

Damage Roll: The damage roll would be 1d8 (or 1s10 if holding weapons in both hands) + 0 (Strength). Total would be = 1d8 or 1d10.

A level 13 Rogue wielding a Rapier and having 20 Dexterity modifier and 10 Strength modifier:

Attack Roll: The Attack roll would be 1d20 + 5 (Dexterity) + 5 (Proficiency). Total would be = 1d20 + 10.

Damage Roll: The damage roll would be 1d8 + 5 (Dexterity) + 7d6 (Sneak Attack for Finesse Weapon and having an adjacent ally). Total would be = 1d8 + 5 + 7d6. 

Sometimes, it may be tough to figure out which ability modifier to use when making an attack. So, let us figure out the modifier while attacking with a d20 roll. 

How Do You Know Which Ability Modifier to Use When Attacking? 

  • The attacks made using ranged weapons use the Dexterity modifier of the character. 
  • The attacks made using melee weapons use the Strength modifier of the character.
  • The weapons with Finesse property use either Strength or Dexterity modifiers of your character. It depends on you which modifier to choose. 
  • If you use a weapon with the thrown property, it uses the same stats when not thrown (that is, STR unless it is a finesse weapon). 

In all the cases and weapons, you add + 2 for level 1 character and occasionally increase proficiency bonus as you level up if you use the weapon with which you are proficient. Page 149 of the Player’s Handbook weapon chart states which weapons have finesse and thrown property. You can also consult page 14 of the PHB to determine which modifier to use. 

FAQs

Here are the answers to some frequently asked questions to assist you further-

Are Missile Attack Bonuses Added to Attack or Damage Rolls?

The missile attack bonus determines if you hit something or not. If you hit something, it is added only to your attack roll. The damage roll determines the amount of damage you caused while attacking the opponent. If you use a crossbow, the damage is only the flat toll from the weapon. You can add the magical enhancement bonus to attack and damage rolls. Use your strength modifier on the damage roll (if it is negative) for the listed missile attack bonus. It means your character would get -1 damage because of low strength. In contrast, if the character has high strength, it would only add to the expensive Composite Bow. 

What Are the Mechanics of Attack and Roll Damage for Hill Dwarf Fighters?

The attack roll bonus is = relevant ability modifier + proficiency bonus (if you are proficient with the weapon) + anything else that says it modifies your attack. 

Similarly, the damage roll for hill dwarf fighter would be = a relevant ability modifier (with squirrely bits when using two weapons during the fight) + anything that says it modifies the damage. 

The strength modifier is the relevant ability modifier for the battleaxe, and the Consitution would be +3. 

For a Basic Unarmed Strike, Is Only the Proficiency Bonus Included in the Attack Roll, or Is the Strength Modifier Also Added?

The unarmed strikes are melee weapon attacks (without using weapons), even though they are not made with weapons, as clarified in the Sage Advice Compendium (SAC). Some attacks count as melee or ranged weapon attacks, even if weapons are not involved in melee attacks. Sometimes, an unarmed strike counts as a melee weapon attack, even though the attacker’s body does not constitute a weapon. 

A “melee-weapon attack” (with a hyphen) means an attack with a melee weapon, as stated in the “Melee Attacks” section of the rules. It means you can use an unarmed strike to make a melee weapon attack without a weapon. The calculation of the attack roll would be d20 + proficiency bonus + Strength modifier.