Baldur's Gate 3 is based on the Dungeons & Dragons 5th Edition ruleset. If you've never played tabletop D&D, the mechanics can feel overwhelming at first. This guide strips away the math and explains exactly what you need to know to dominate combat.
1. The Action Economy (What You Can Do)
In turn-based combat, victory belongs to whoever takes the most effective turns. Every single turn, each character gets three distinct resources to spend:
🟢 Action (Main)
Your most powerful move. Used to attack with a weapon, cast a leveled spell, Dash (double movement), or help a downed ally.
🟠 Bonus Action
A smaller, secondary action. Used to drink a potion, Shove an enemy, Jump, or cast specific quick spells (like Healing Word).
🔵 Movement
The distance you can walk. Usually 9m (30ft). You can break this up (move 4m, attack, move 5m away).
The Golden Rule: Never end your turn with a green circle (Action) or an orange triangle (Bonus Action) unspent if you can help it. Even Shoving an enemy 1 meter backwards is better than doing nothing with your bonus action.
2. Advantage & Disadvantage (The D20)
Whenever you attack someone, the game secretly rolls a 20-sided die (D20) to see if you hit. If you roll high enough, you deal damage. If not, you miss. But there are ways to cheat the odds.
📈 Advantage (Roll Twice, Take Highest)
When you have Advantage, the game rolls two D20s and uses the higher number. This massively increases your chance to hit and land critical strikes.
How to get it: Attack from hiding (Stealth), attack an enemy that is Prone (knocked down), or use spells like Faerie Fire.
📉 Disadvantage (Roll Twice, Take Lowest)
The opposite. The game rolls two dice and forces you to use the lowest number. You will almost certainly miss.
How to avoid it: Do not shoot ranged weapons (bows/spells) when an enemy is in melee range right next to you (Threatened). Do not attack in total darkness without Darkvision.
3. Spellcasting 101: Slots vs. Cantrips
Magic isn't free. Understanding the difference between your two types of spells is crucial for classes like Wizard, Sorcerer, and Cleric.
Cantrips are level 0 spells. They cost no resources and can be cast infinitely, every single turn. Think of them as a wizard's basic attack. Examples: Fire Bolt, Ray of Frost, Eldritch Blast. Always use these when you want to save your big spells for a boss.
Unlike other RPGs with a blue Mana bar, BG3 uses Spell Slots. Think of them as "bullets" in a chamber. If you have three Level 1 Spell Slots, you can cast exactly three Level 1 spells (like Magic Missile or Cure Wounds). Once they are gone, you cannot cast leveled spells until you take a Long Rest at camp to reload them.
Note: You can "upcast" a Level 1 spell using a Level 2 slot to make it hit harder.
Some powerful continuous spells (like Bless or Cloud of Daggers) require Concentration. You can only concentrate on ONE spell at a time. If you cast a second Concentration spell, the first one instantly cancels! Furthermore, if the caster takes damage, they must pass a Constitution saving throw or they will drop the spell.
4. Stats & Proficiency
Stats don't just increase by arbitrary numbers. Every 2 points above 10 gives you a +1 Modifier. This modifier is added to your dice rolls.
- 10 or 11 = +0
- 12 or 13 = +1
- 14 or 15 = +2
- 16 or 17 = +3
- 18 or 19 = +4
- 20 = +5
Pro-Tip: Because odd numbers (like 17) give the exact same bonus as the even number below them (16), leaving a stat at 17 is technically a waste of points unless you plan to take a feat that adds +1 to it later.
Proficiency Bonus
This is a flat bonus (starts at +2 at Level 1, scales to +4 at max level) added to things your character is trained in. If you are proficient in Longswords, you add your Strength modifier AND your Proficiency bonus when swinging one. If you equip a weapon you are not proficient with, you will miss almost every attack.
5. Crucial Early Game Tips
-
1
Examine Everything
Right-click (or press Square/X) on enemies and select Examine. This pauses the game and shows you their resistances and weaknesses. If a skeleton is resistant to piercing damage, put away your bow and pull out a blunt mace.
-
2
Throw Healing Potions
You don't need a cleric to heal an ally. Any character can use their Action to "Throw" a healing potion directly at a downed party member's body. The splash zone will heal them and pick them back up!
-
3
Use the Environment
Water conducts electricity. Grease and Webs are highly flammable. If enemies are standing in a puddle, casting a lightning spell on the water will shock all of them at once. Always look for explosive barrels to ignite.
-
4
Rest Often
Do not hoard your Camp Supplies. Long Rests are necessary not only to regain your spell slots and HP, but also to progress companion dialogue and storyline events at camp. If you don't rest enough, you will miss out on crucial story beats.
6. Short vs Long Rests
Knowing when and how to rest is vital to surviving the early encounters of Act 1.
💤 Short Rests
You get 2 Short Rests per day (3 if you have a Bard in the party). These instantly heal 50% of your max HP. They also refresh specific class resources: Warlock spell slots, Fighter Action Surge, and Monk Ki Points.
⛺ Long Rests
Ends the day. Requires 40 Camp Supplies (80 in Tactician/Honour Mode). Restores all HP, all spell slots, all once-per-day abilities, and clears most debuffs. Important: Long resting is how you trigger companion cutscenes and story progress!
7. Party Composition
A balanced party of 4 makes combat significantly easier. Try to fill these four roles:
| Role | Purpose | Best Classes |
|---|---|---|
| Frontline Tank | Absorbs damage, blocks pathways, and punishes enemies trying to reach your squishy casters. | Fighter (Lae'zel), Barbarian (Karlach), Paladin |
| Support / Healer | Casts 'Bless', throws healing potions, and revives downed allies from a distance. | Cleric (Shadowheart), Bard |
| Utility / Striker | Picks locks, disarms traps, and deals massive single-target damage (Sneak Attacks). | Rogue (Astarion), Ranger, Monk |
| AoE Caster | Crowd control (Web, Grease) and area damage (Fireball) to clear out multiple weak enemies. | Wizard (Gale), Sorcerer, Warlock (Wyll) |
8. Skills & Exploration
The "Guidance" Cantrip is Overpowered
If you have Shadowheart in your party, make sure she knows the Guidance cantrip. Before ANY dialogue check (Persuasion, Deception) or lockpicking attempt, cast Guidance to add a free 1d4 to your roll. This stacks with almost everything and costs zero spell slots.
- Always carry a Shovel: When your characters succeed a passive Perception check while walking, they usually spot a hidden dirt mound. You cannot dig up the treasure chest unless someone in the party holds a Shovel in their inventory.
- Trap Disarm Toolkits: Just like Thieves' Tools for locks, these are consumed if you fail a roll to disarm a trap. Buy them from every merchant you see!
- Speak with Animals / Dead: Spells or potions that grant these effects unlock dozens of secret quests and alternative solutions. A dead body or a random rat might know the password to a hidden vault!
💬 Community Strategies & Discussion
Did you find a hidden chest? Struggling with a boss? Share your tips and questions with other mercenaries below!