To determine an ability modifier without consulting the table, subtract 10 from the ability score and then divide the total by 2 (round down).
Because ability modifiers affect almost every attack roll, ability check, and saving throw, ability modifiers come up in play more often than their associated scores.
Player’s Handbook, page 173
DnD 5e Modifiers
Rolling dice is what Dungeons and Dragons is all about — watching those clickety-clack math rocks determine the fate of heroes is a ton of fun. But if DnD were simply a game of chance, nothing would separate the warriors from the mages, the diplomats from the savages. In short, the role-playing aspect of the game would fall on its face almost immediately.
That’s where modifiers come in. DnD modifiers affect many of the dice rolls that you make throughout an adventuring day and can substantially increase your character’s odds of success…or make them worse. As your character grows in power, so do these modifiers, which makes your character better at whatever they specialize in.
This article will cover:
How DnD modifiers work
How to calculate your modifiers in DnD
The relationship between ability scores and modifiers
What Is a DnD Modifier?
A DnD modifier is a positive or negative number that changes the result of a natural die roll. Modifiers exist to highlight a character or creature’s strengths and weaknesses.
These modifiers are used in a number of circumstances, explained below.
How Do You Determine DnD Modifiers?
Modifiers are determined by your character’s ability scores, as well as your proficiency bonus:
Ability Score Modifiers
Your six ability scores are:
As your ability scores rise (every four levels for most classes), so do their associated modifiers. To calculate your ability modifier, subtract 10 from the abilty score and divide the result by 2, rounded down. Or, consult this table (PHB 173):
Players can’t attain ability scores greater than 20, so +5 is effectively the cap on ability modifiers under normal circumstances.
In addition to ability score modifiers, a character also has a proficiency bonus. This is an extra modifier that gets added to skills and saving throws you are proficient in, as well as attack and damage rolls made with weapons you’re proficient with.
Profiency bonus scales with character level, like so:
By knowing your ability score modifiers and proficiency bonus, you can figure out every other modifier you need to use.
What Are Common DnD Modifiers?
The most common DnD modifiers are:
When you make a weapon attack, you add your attack bonus to the result of a d20 roll. Here’s how to calculate your attack bonus:Non-Finesse Melee Weapon: Strength Modifier + Proficiency Bonus (if proficient with the weapon)
Non-Finesse Ranged Weapon: Dexterity Modifier + Proficiency Bonus (if proficient with the weapon)
Finesse Weapon: Strength or Dexterity Modifier + Proficiency Bonus (if proficient with the weapon)
Attack Damage Bonus
Your attack damage bonus is equal to the ability modifier you used for the attack roll. So if you used Strength for your attack roll, your Strength ability modifier is added to the weapon’s damage roll.
Skill checks use the same modifier as whatever ability is associated with the skill. For example, your Charisma modifier is used to determine your Deception, Intimidation, Performance, and Persuasion skill checks. So if your Charisma modifier is +2, then your modifier for each of those skills is also +2.
You can also be proficient in a skill. If you are, you add your proficiency bonus to its modifier. To continue our example, if your proficiency bonus is +2 and you are proficient in Deception, then your Deception modifier is +4. (+2 from Charisma and +2 from proficiency).
Saving throws use the same modifier as the associated ability. For example, your Charisma saving throw modifier is equal to your Charisma ability modifier.
You can also be proficient in a saving throw. If you are, you add your proficiency bonus to its modifier.
Your initiative modifier is equal to your Dexterity ability modifier. The Alert feat and other subclass features can provide additional bonuses to your initiative modifier.
Armor Class Modifiers
Here’s how to calculate your armor class:Light Armor: If your character is wearing Light Armor, you add your Dexterity modifier to the Armor Class provided by the armor itself.
Medium Armor: If your character is wearing Medium Armor, you add your Dexterity modifier to the Armor Class provided by the armor itself, but this modifier is capped at +2
Heavy Armor: If your character is wearing Heavy Armor, there is no modifier added to determine your AC. The armor’s AC is your character’s AC.
Spell Attack Bonus
Your spell attack bonus is equal to your spellcasting ability modifier plus your proficiency bonus. So if your class uses Wisdom as their spellcasting ability and has a +3 Wisdom modifier and +2 proficiency bonus, your spell attack bonus modifier is +5.
You add this number to any ranged or melee spell attack.
Spell Save DC
Your spell save DC isn’t really a modifier, but it does grow in relation to other modifiers. Your spell save DC is equal to 8 + your spellcasting ability modifier + your proficiency bonus.
You use this number to set the difficulty class for spells you cast that force a creature to make a saving throw.
Ability Scores and Modifiers in 5e
Since “ability modifiers come up in play more often than their associated scores,” many new players wonder why DnD 5e bothers with ability scores at all. The traditional answer given is, well, tradition.
Ability scores go way back to the first edition of Dungeons and Dragons, and some people see them as an annoying holdover.
However, ability scores are sometimes used in the fifth edition of DnD:
Prerequisite for the Grappler feat
Prerequisite for multiclassing into Fighter, Monk, Ranger, or Rogue
Prerequisite for Defensive Duelist and Skulker feats
Common houserule: used as an initiative check tie-breaker
How long you can spend in frigid water
Movement speed in the Astral Plane
Determining whether a creature is a valid target for a spell or effect (e.g., Animal Friendship)
Determines the DC of ciphers made via the Linguist feat
Prerequisite for multiclassing into Wizard
Prerequisite for the Ritual Caster feat
Prerequisite for multiclassing into Cleric, Druid, Monk, or Ranger
Prerequisite for the Ritual Caster feat
Prerequisite for multiclassing into Bard, Sorcerer, or Warlock
Prerequisite for the Inspiring Leader feat
As you can see, ability scores have been pretty much relegated to being a pre-requisite for multiclassing and certain feats.
Your Strength ability score is the most common to actually come up during a game (jumping and carrying things). As a DM, I also use creatures’ Dexterity scores as a tie-breaker for equal initiative rolls.