Baldur's Gate 3 Abilities and Dice Rolls Explained

Quick answer: Most BG3 checks start with a twenty-sided die, then add an ability modifier and any applicable bonuses. Ability checks and saving throws must meet a Difficulty Class (DC); attack rolls must meet the target’s Armour Class (AC). A large damage number does not improve your chance to hit.

BG3 adapts fifth-edition D&D, but its own spell descriptions and character sheet govern your decisions. This beginner guide covers the unmodded Patch 8 rules, without requiring tabletop experience or a particular character build. Combat difficulty can still vary with your chosen mode.

Content warning: The game contains mature violence, nudity and sexual content. This guide discusses only non-graphic gameplay systems.

Read Your Ability Modifiers

The large ability score is not the number added to your roll. Its modifier is the important number: subtract 10, divide by two, and round down.

Ability score	Modifier
8-9	-1
10-11	+0
12-13	+1
14-15	+2
16-17	+3
18-19	+4
20	+5

Raising a score from 16 to 17 leaves its modifier at +3. Raising 17 to 18 changes it to +4. When allocating ability points, look for the next modifier threshold instead of assuming every point improves your rolls immediately.

The six abilities serve different jobs:

Ability	Examples of what it affects
Strength	Ordinary melee attacks and Athletics
Dexterity	Ranged weapons, Sleight of Hand and Stealth
Constitution	Maximum hit points and concentration saves
Intelligence	Arcana, Investigation and wizard spellcasting
Wisdom	Perception, Insight and cleric or druid spellcasting
Charisma	Persuasion, Deception and bard, paladin, sorcerer or warlock spellcasting

Constitution has no associated skills. That does not make it irrelevant to a character who wants to keep a spell running while taking damage.

Know Which Roll You Are Making

Read a roll as d20 + relevant ability modifier + applicable proficiency + other bonuses or penalties. Meeting the target number is enough; you do not have to exceed it.

• Ability check: Can you complete a task, such as persuading someone or picking a lock?
• Attack roll: Does your weapon or spell attack connect with the target’s AC?
• Saving throw: Do you resist or reduce an effect targeting you?

For a hypothetical DC 15 check with a total +5 bonus, a die result of 10 reaches 15 and succeeds. A 9 reaches only 14. The DC is the required final total, not necessarily the number you need on the die itself.

What Natural 1 and Natural 20 Mean

“Natural” means the die before modifiers. Normally in BG3, a natural 1 fails an ability check or attack, while a natural 20 succeeds. A final total of 20 obtained by rolling 15 with +5 is not a natural 20. Equipment that prevents critical hits can make a natural-20 attack check AC normally instead of automatically hitting.

Do not extend that rule to every saving throw. Ordinary saves use their final total; concentration and dialogue saves have special natural-roll outcomes.

Add Proficiency Only Where It Applies

Proficiency represents training, separately from the ability modifier. Its base bonus is +2 at character levels 1-4, +3 at 5-8, and +4 at 9-12. These use total character level even if you multiclass. Explorer adds another +2 to proficiency bonuses, and Custom settings can change them. The example below uses the base bonus.

A level-3 character with Charisma 16 gets +3 from Charisma. With Persuasion proficiency, their ordinary Persuasion bonus becomes +5 before other effects. Without that proficiency, it remains +3. Expertise doubles the proficiency contribution, so the same example would reach +7, not +9.

Training is specific. Persuasion proficiency does not grant proficiency in Charisma saving throws. Weapon proficiency improves attacks with that weapon; it does not normally add the proficiency bonus to damage. Getting the same proficiency twice does not double it.

Prepare for Dialogue and Exploration Checks

Look at the named skill before selecting a dialogue approach. Persuasion and Deception share Charisma, but proficiency can make one stronger than the other. Likewise, a high Dexterity score and Sleight of Hand proficiency are separate contributions to a lockpicking attempt.

Use Add Bonus on a check screen to inspect available assistance before rolling. Guidance adds 1d4 to ability checks: that is a separate four-sided die, not a fixed +4. Bless instead helps attack rolls and saving throws; it is not a substitute for Guidance on an ordinary Persuasion check.

Check the helper’s existing concentration before adding a spell. Guidance and Bless both require concentration, so the same caster cannot maintain both. Adding Guidance can end that caster’s Bless.

Some exploration checks happen automatically, including Perception near traps. Do not expect every useful skill to present a dialogue-style dice screen first.

Separate Accuracy from Damage

For an ordinary weapon attack, first compare the attack total with AC. Only a hit proceeds to its damage roll. A hypothetical +5 attack against AC 15 connects on a die result of 10, regardless of how large the weapon’s damage dice are.

Melee weapons generally use Strength; ranged weapons use Dexterity. Finesse weapons use whichever of Strength or Dexterity is higher. Spell attacks use the relevant spellcasting ability. Check the attack you actually selected, especially when a class feature changes its normal ability.

Damage notation describes another calculation. 1d8+3 means one eight-sided die plus three, giving 4-11 damage before other effects. A normal critical hit doubles the damage dice, not the flat bonus: that example becomes 2d8+3, not 2d8+6. Some targets have protection against critical hits.

Understand Saving Throws and Concentration

Some spells ask the enemy to save instead of asking you to attack their AC. The spell’s listed save ability matters. A target that is difficult to hit with weapons is not automatically equally good at every saving throw.

A typical spell save DC is 8 + proficiency bonus + casting ability modifier. With +2 proficiency and a +3 casting modifier, that is DC 13. The defender rolls against it. A successful save may prevent the effect or merely reduce it; read the spell’s result rather than assuming success means zero damage.

Keeping a Spell Active

Taking damage while concentrating triggers a Constitution save. Its DC is 10 or half the damage taken, whichever is higher. For example, 12 damage means DC 10; 30 damage means DC 15.

Failed concentration ends the spell. Casting another concentration spell also ends the first, without needing an enemy to interrupt you. Before using a new spell, check whether you are replacing an effect you still need.

Use Advantage Without Wasting It

Advantage rolls two d20s and keeps the higher. Disadvantage keeps the lower. Neither changes the damage dice. With results of 6 and 17, advantage keeps 17 before adding modifiers; disadvantage keeps 6.

Multiple advantage sources do not grant extra dice. Any advantage and disadvantage cancel to one die, even if you have several advantage sources and only one disadvantage source.

When your chance to hit looks unexpectedly poor, look for disadvantage before spending another buff. Being Threatened can penalize ranged attacks. Adding more advantage after it is already active will not overcome a remaining disadvantage source by sheer quantity.

Common Mistakes

1. Comparing scores instead of modifiers. Check whether an increase crosses an even-number threshold.
2. Treating damage as accuracy. Compare the attack bonus and target AC separately from damage dice.
3. Using the wrong bonus for a check. Guidance, Bless and proficiency have different jobs.
4. Replacing concentration accidentally. Read the concentration tag before adding another spell.
5. Expecting high AC to solve every threat. Saving throws test different defenses.