How spells, cantrips & Spell Slots work - Baldur's Gate 3

Learn everything you need to know about spells, from preparing and casting them to how Spell Levels, cantrips, and concentration works in Baldur's Gate 3.

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Spells, cantrips, Spell Slots, and even the Spellbook are all mystical and mysterious mechanics in Baldur’s Gate 3. Even those with a firm grasp on Dungeons & Dragons might find spell usage in-game confusing at first. Whether you’re a veteran or just starting your journey, this guide will look to either refresh your memory on sorcery and spells or teach you everything you need to know.

If you’re brand new to Baldur’s Gate 3 or Dungeons & Dragons, make sure you read over our guide about how combat works. That introduces the basics of fighting, including a look at spells.

What are spells?

The Guiding Bolt spell being cast

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At the very basic level, spells are abilities in Baldur’s Gate 3 that enhance you and your allies, buff your weapons, debuff foes, deal damage, interact with the environment, and much more. They can be cast in and out of combat, memorized, and learned from various sources. Spells can be class-specific or even cast by reading a scroll. They’re as wonderful and versatile as they are complex.

Some spells are classified as Actions while others are Bonus Actions. The difference between these is generally related to the power and effect of a spell. A really strong spell is more likely to be an Action.

Casting a spell requires it to use an Action or a Bonus Action as well as a Spell Slot, which is basically a charge. You can learn more about Spell Slots below.

What are cantrips?

The Common tab in the Spellbook with arrows pointing at cantrips

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Cantrips are sort of “mini” spells. These don’t require preparing, can be cast without using Spell Slots, and can be cast at will. Because cantrips have fewer requirements to cast, they are often far less powerful than normal spells.

What are Class Actions & Ritual Spells?

A Class Action is highlighted

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Some Class Actions look strikingly similar to spells, but they are technically different. For example, the Paladin has a Class Action called Lay on Hands. This does not use Spell Slots to cast but still looks and feels like a spell. In fact, it uses a class-specific resource (Lay on Hands charges).

Ritual Spells are also similar to Class Actions but are more aligned with spells. These can be cast in combat and out of combat, but casting Ritual Spells outside of combat does not consume a Spell Slot. Spells like disguising yourself or talking with the dead are Ritual Spells.


The Spellbook is where you can see spells you know, spells you have prepared, their cost, and more. If you’re using a class that can cast spells, familiarize yourself with the Spellbook. Press the K key to open the Spellbook or navigate to it through the Inventory screen (players using controller can see the Spellbook by pressing right trigger and selecting it):

  1. Press the I key to open the inventory
  2. At the top of the inventory select the Spellbook icon
The Spellbook open at camp showing various spells and cantrips

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The first tab will be all the spells and Class Actions specific to your class. This will show any class-specific elements including Class Action Resources, what stat is used for casting spells, your Spell Save Difficulty Class, and Spell Attack Damage (more on these below).

The Common tab contains spells or moves specific to your race, armor you’re wearing, or moves available to everyone (Dash, Shove, etc). This is where you can see moves for any weapons you’re holding.

The Reactions tab is for any spells or abilities that can be Reactions (Reactions are on the Character Sheet when using controller). Reactions are triggered at any time in response to outside stimulus (an enemy that runs away from you triggers an Attack of Opportunity).

The Class and Common tab will have a breakdown of the tiers of spells, as indicated by the Roman numerals. It will also display cantrips (labelled with a square), Class Actions (a circle), and spells that are always prepared (infinity sign).

The icon of the book with the flame (the Spellbook icon) is for the row that shows all your prepared spells. Only the spells in this row can be cast, all the other spells are waiting on the sidelines until you assign them to the row.

When using a controller, many of these screens will be different, but they will include more information. For example, instead of spells labelled with an infinity sign, the UI will say “Always Available Spells”. Click the right thumbstick to see tooltips whenever you highlight something.

How to prepare spells

Unlike cantrips which are always prepared, spells must be prepared before they can be cast. Your wizard might be aware of 100 different spells, but it has to select which spells it wants to memorize in order to cast them in combat or while exploring.

A spell is being selected in the Spellbook to be removed from the Prepared row
The highlighted row shows all the spells you have prepared. Below these spells are rows of the spells you know, separated into Spell Slot Levels.
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Spells can be prepared in the Spellbook or in the level up screen. To prepare a spell in the Spellbook, navigate to the Spellbook and then go to the first tab (the class tab). The highlighted row with the Spellbook icon is where all your prepared spells sit.

Below the highlighted row will be spells you know, separated into different tiers called Spell Levels. A spell with a golden border is a spell you have prepared. Click a highlighted spell to remove it from the prepared section and click another one to prepare it.

The Spellbook shown with controller UI

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When using a controller, the UI will be much different. You will need to press a specific button to Prepare Spells (shown at the top of the screen). A new screen will open where you can see Prepared Spells and Known Spells. 

Spell Slots

The Spell Slots circled on the HUD
The number of boxes indicates how many Spell Slots (charges) you have. Here you can see there are four charges of Level 1 and three charges of Level 2 spells.
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Spells Slots are the charges that get consumed whenever you cast a spell. Classes can have a different number of charges; my paladin has three Spell Slot Level 1 charges while my cleric has four. That means my cleric can cast one more spell than my paladin can. Different spells will require different Spell Slot Levels.

Spell Slot Levels

The level up screen showing a Wizard picking which spells to unlock, a Spell Slot tooltip is visible
Spells will have a Roman numeral indicating what Spell Slot Level they belong in.
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This is where things can get complicated. Spell Slot Levels are used to separate spells of differing power. The more powerful a spell, the higher the Spell Slot Level requirement will be. For example, a spell that sits in the Spell Slot Level 7 category will be much more powerful than a spell that uses Spell Slot Level 1.

Within the Levels is where the Spell Slots (charges) are stored. Using Shadowheart as an example, early on she can have four charges in Spell Slot Level 1 and two charges in Spell Slot Level 2. This means she can cast only two spells from Spell Slot Level 2 before she’s out of charges and will need to perform a Short or Long Rest to get them back (she would still be able to cast smaller, Spell Slot Level 1 spells).

The number of Spell Slot Levels and the number of charges within increases as your character levels up. Multiclassing can have an effect on these numbers too. However, the higher the Spell Slot Level, the fewer charges it contains.

Upcasting spells

One useful mechanic of Spell Slot Levels is upcasting. This is a mechanic that lets you take a lowly spell and use a higher Spell Slot Level to cast it. For example, you might use a spell from Spell Slot Level 1 and cast it using a higher level, like Spell Slot Level 3.

Lunar Mends is highlighted in the spell section as a bear prepares to cast it
Here you can see Lunar Mend can be upcast across all three available Spell Slot Levels. Upcasting it improves its healing capabilities.
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A spell that can be upcast will offer the option to upcast when you select it. The tooltip will have an icon indicating it is being upcast and the tooltip will inform you whether there is an advantage to upcasting.

There are a few reasons why you might want to upcast a spell. First is that you might have run out of lower Spell Slot Levels but still need or want to cast the spell. Another reason is that some spells gain a bonus when upcast. For example, the Lunar Mend spell sits in Spell Slot Level 1 but it can be upcast into Level 2 (or Level 3) to provide more healing!

The disadvantage of upcasting is that it will consume a charge from the higher Spell Slot Level. This means you will have one less charge to cast a powerful spell. Additionally, some spells won’t receive any bonus when you upcast, so make sure you read the tooltip and choose whether you need to upcast.

It’s also worth mentioning that spells cannot be downcast. You can’t squish a big powerful Level 9 spell down into a little Level 1.

How to get more spells

Any class that uses spells will typically be able to learn new spells each time they level up. The level up screen will provide a few options to choose from. Additionally, spells can be learned out in the wild or from scrolls.

The HUD showing the cost to learn a spell by consuming a spell scroll
Gale can study scrolls (consuming them) to permanently learn a spell.
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If you're a Wizard and you find any spell scrolls, you (or Gale) can learn the spells from the scrolls. This is a class-specific ability, so it’s not going to be available to all adventurers.

There is a gold cost associated with learning a spell and the scroll will be consumed. There is also a level restriction: if you’re not a high enough level, some spells cannot be learned until you level up.

The Spellbook with the learn spell button circled
The icon lets you learn spells directly from the Spellbook.
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To learn the spell, either right-click a spell scroll and select "Learn spell" or open the Spellbook and click the icon of the book with the plus sign. A new panel will open up that shows all spell scrolls. This lets you transcribe spells into your Spellbook. The character that is learning the spell must have gold in their inventory.

How to recharge spells

As mentioned above, using a spell will typically consume a Spell Slot. In order to recover Spell Slots and thus “recharge” your spells, you will either need to do a Short Rest or a Long Rest. Some spells only need a Short Rest to be recouped while other, more powerful, spells will require you going to camp and sleeping the night away. Inspect the spell to see what it needs to be recharged.

Spellcasting Ability

The Spellbook showing the Spellcasting Ability

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This is the ability that influences the chance your spell will hit its target. This is also responsible for how many spells you can prepare (for some classes). These three letters are a shortening of the main abilities:

  • STR: Strength
  • DEX: Dexterity
  • CON: Constitution
  • INT: Intelligence
  • WIS: Wisdom
  • CHA: Charisma

Increasing the ability that spellcasting relies on will improve your chances of having the spell hit. You’ll be able to increase an ability every few levels.

Spell Save DC

The Spellbook showing the Spell Save Difficulty Class

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Spell Save DC, or Difficulty Class, dictates what number an enemy has to roll when you target them with your spell in order to avoid getting hit or succumbing to your spell’s effect (a Saving Throw).  This number is a combination of your base Difficulty Class (usually 8), your spellcasting ability (noted above), and your proficiency.

If the enemy fails to meet or exceed your Spell Save DC, they will fail the Saving Throw and be hit. This all happens automatically during combat and is why you might see the “miss” text appear whenever you cast a spell.

Spell Attack

The Spellbook showing the Spell Attack

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This number dictates any bonus your melee spells and ranged spell attacks receive. Some spells receive an improved chance to hit based on the Spell Attack number.


The Shield of Faith spell is being cast, showing it requires concentration

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Concentration is a type of spell or Class Ability that requires focus in order to maintain. These are often spells that last multiple turns. A spell that requires concentration will end if your character is hit or you cast another spell that requires concentration.

Whenever an enemy attacks you while your character is concentrating on a spell, you will automatically perform a Saving Throw. If you succeed this dice roll, you will not lose concentration and the spell will continue.

There is a lot to learn and remember when it comes to spells in Baldur’s Gate 3. Your first stop should be to investigate the Spellbook and familiarize yourself with the language used, specifically Spell Slot Levels. Once you wrap your head around Spell Slots, the rest will seem easier by comparison. Take a moment to peruse our Baldur’s Gate 3 strategy guide for more helpful explanations of this complex game.

Guides Editor

Hailing from the land down under, Sam Chandler brings a bit of the southern hemisphere flair to his work. After bouncing round a few universities, securing a bachelor degree, and entering the video game industry, he's found his new family here at Shacknews as a Guides Editor. There's nothing he loves more than crafting a guide that will help someone. If you need help with a guide, or notice something not quite right, you can Tweet him: @SamuelChandler 

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