Core Mechanics · BG3 Guide

The action economy

Each turn every character gets one of each resource below. Winning in BG3 is mostly about spending all of them, every turn, on every character.

Resource	Typical uses	Tip
Action	Attack, cast a spell, Dash, Help, Hide, Dip, throw	Extra Attack (level 5 martials) gives two attacks per Action.
Bonus Action	Shove, Jump, drink a potion, off-hand attack, many class features	Drinking a potion is a bonus action — throwing one at an ally is an Action but works on downed allies.
Movement	Walking, climbing, jumping distance	Jump costs movement and a bonus action but ignores difficult terrain and avoids opportunity attacks if you jump away.
Reaction	Opportunity attacks, Shield, Counterspell, Hellish Rebuke, Riposte	Set reaction prompts in the character's Reactions tab so you aren't asked every time.

Rule of thumb If a character ends their turn with an unused bonus action, ask whether they could have Shoved, Jumped to high ground, drunk a potion, or used a class bonus action (Cunning Action, Healing Word, Misty Step, Flurry of Blows, Bardic Inspiration).

Hitting things: advantage, high ground and bonuses

Advantage rolls two d20s and keeps the higher (roughly +4 to +5 on average). Sources: attacking from stealth, attacking prone/blinded/restrained targets, Faerie Fire, Reckless Attack, Guiding Bolt, being unseen.
Disadvantage keeps the lower roll. Causes: ranged attacks while an enemy is next to you, attacking in darkness without Darkvision, being poisoned, frightened or prone, heavy obscurement.
High ground gives +2 to ranged attack rolls; low ground gives −2. Archers and casters should always be up high.
Advantage and disadvantage cancel out. Several sources of either still only count once.
Critical hits on a natural 20 double your damage dice. Champion, Hexblade and some items expand the crit range to 19 or 18.

Surfaces, elements and the environment

The environment is a weapon. Many of the best guides rank environmental play as the single biggest skill jump for new players.

Surface	Effect	Combo
Water	Applies Wet: vulnerable to lightning and cold, resistant to fire	Create Water → Lightning spell for double damage on everyone wet.
Grease / Oil	Difficult terrain, chance to fall prone	Ignite for a large fire surface. Explosive barrels do the same.
Ice	Characters can slip and fall prone	Prone enemies give melee attackers advantage.
Fire	Burning damage each turn	Water or Create Water puts it out.
Web	Restrained / Enwebbed	Webs are flammable — burn them to damage and free targets.
Darkness / Fog	Heavily obscured: blinds those inside	Devil's Sight lets warlocks see in magical Darkness and shoot with advantage.

Shove enemies off ledges, into chasms or into lava. Falling damage scales with distance, and enemies pushed off the map die instantly.
Throw is an Action that uses Strength: heavy objects, potions and even other creatures can be thrown.
Dip (bonus action) coats your weapon in a nearby fire surface or candle for extra 1d4 fire damage.
Destroy wooden scaffolding, chandeliers and walls to drop things on enemies.

Stealth, surprise and ambushes

Enemies have vision cones (toggle with Shift on PC). Stay out of red cones while Hidden.
Attacking from stealth starts combat with Surprise for enemies that fail their Perception check — they lose their first turn.
The "pre-buff and ambush" opener: hide the whole party, move everyone into position in turn-based mode (Space on PC), cast buffs, then open with your biggest attack.
Characters out of combat can still act in real time while others fight. Use this to reposition or rescue allies.
Pickpocketing and lockpicking are skill checks — save first. Getting caught can make whole areas hostile.

Resting and camp supplies

Short rest: two per long rest. Restores half of each character's HP and many class resources (Warlock slots, Action Surge, Ki, Channel Divinity).
Long rest: costs 40 camp supplies (80 on Tactician and Honour). Fully restores HP, spell slots and abilities.
Partial rest: without enough supplies you still restore half HP and half spell slots.
Story fires in camp. Approval scenes, romances, and many companion quests only advance during long rests. Don't skip them on a first run.
Timed content is rare but real: freeing Halsin and the Grove arc, Act 2 Moonrise prisoners, and several Act 3 quests can fail if you rest too much at the wrong moment. The game usually signals urgency in dialogue.

Ability checks, saving throws and Inspiration

Dialogue checks roll a d20 + modifier vs a DC. Natural 20 always succeeds; natural 1 always fails.
Guidance (Cleric/Druid cantrip) adds 1d4 to ability checks — keep a caster with it in your party for dialogue.
Inspiration is earned by acting in character for your background; spend it to reroll a failed check. You can hold up to 4 (it caps out, so spend it).
Saving throws resist spells and effects. Proficiency comes from your first class only — another reason multiclass order matters.
Swap the talker: In party chat, any character can initiate dialogue. Use your highest-Charisma character for Persuasion and Deception.

Concentration

Many of the strongest spells (Bless, Hold Person, Haste, Spirit Guardians, Hunger of Hadar, Hex) require Concentration. You can maintain only one at a time, and taking damage forces a Constitution save to keep it.

War Caster feat or Resilient (Constitution) make concentration far more reliable.
Haste is the best and most dangerous: if concentration breaks, the target is Lethargic and loses a turn.
Spread concentration spells across characters rather than stacking them on one caster.

Multiclassing essentials

You need 13 in the primary stat of each class to multiclass in tabletop; in BG3 there are no stat requirements.
Your first class determines saving throw proficiencies and some armour/weapon proficiencies. Starting Fighter/Paladin gives heavy armour; starting Sorcerer gives Constitution saves.
Spell slots combine across full casters (and half-casters at half rate). Warlock Pact slots stay separate but refresh on short rest.
Extra Attack doesn't stack. Taking level 5 in two martial classes is wasted.
Max level is 12. Feats arrive at class levels 4, 8, 12 (Fighters also at 6, Rogues at 10).

Systems the game doesn't explain

Karmic Dice (on by default) reduces long streaks of bad or good rolls. Turn it off for true randomness.
Illithid powers: Consuming tadpoles unlocks strong abilities like Cull the Weak and Displacer Beast's Displacement. They have story implications — companions such as Lae'zel and Karlach react differently, and consuming the Astral-Touched tadpole permanently changes your character's appearance and options in the finale.
Elixirs last until long rest and stack with potions. Elixirs of Hill or Cloud Giant Strength set Strength to 21 or 27 — huge for throwers and melee.
Hirelings (Withers, Act 1) are recruitable mercenaries if you want a different party composition.
Dropping concentration to recast is free — right-click the concentration icon.
No free hand needed for spells. Unlike tabletop, you can cast with a weapon and shield equipped, so sword-and-board casters lose nothing.