BG3 Multiclass Spell Slot Calculator
Plan your perfect Baldur’s Gate 3 build by calculating your spell slots for any multiclass combination.
Character Level Input
Total Spellcaster Level
This value determines your shared spell slots.
Spellcasting Slots (Long Rest)
| Level 1 | Level 2 | Level 3 | Level 4 | Level 5 | Level 6 |
|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 | 0 |
Warlock Pact Magic Slots (Short Rest)
| Slot Level | Number of Slots |
|---|---|
| – | 0 |
What is a BG3 Spell Slot Calculator?
A bg3 spell slot calculator is an essential tool for players of Baldur’s Gate 3 who want to experiment with multiclassing spellcasters. In BG3, when you combine different spellcasting classes, your total number of spell slots is determined by a special formula, not just by adding them together. This calculator automates that complex calculation, showing you precisely how many spells of each level you can cast.
Whether you’re blending a Cleric with a Wizard or a Paladin with a Sorcerer, understanding your effective “spellcaster level” is crucial for planning a powerful build. This tool helps you see the impact of adding a level to one class versus another, ensuring you reach key spell level thresholds exactly when you want to. It’s designed for both theory-crafting experts and players new to the complexities of D&D 5e multiclassing rules that Baldur’s Gate 3 is built upon.
The BG3 Spell Slot Formula Explained
In Baldur’s Gate 3, spell slots for multiclassed characters are determined by calculating a “Total Spellcaster Level.” This is a consolidated level that the game uses to look up your final spell slot count on a master progression table.
The formula is:
Total Spellcaster Level = (Sum of Full Caster Levels) + floor(Sum of Half Caster Levels / 2) + floor(Sum of Third Caster Levels / 3)
Warlock levels are not included in this calculation, as their Pact Magic slots are a separate resource. Here’s how different classes contribute:
| Caster Type | Classes | Contribution to Spellcaster Level | Typical Range |
|---|---|---|---|
| Full Caster | Cleric, Wizard, Sorcerer, Druid, Bard | Each level in these classes counts as one full level. | 1-12 |
| Half Caster | Paladin, Ranger | Levels are added together, divided by two, and rounded down. | 2-12 (need 2 levels to contribute) |
| Third Caster | Fighter (Eldritch Knight), Rogue (Arcane Trickster) | Levels are added together, divided by three, and rounded down. | 3-12 (need 3 levels to contribute) |
| Pact Magic | Warlock | Does not contribute to this total. Has its own separate slots. | 1-12 |
Once your Total Spellcaster Level is found, the game grants you spell slots as if you were a single-classed character of that level. For more details, see this BG3 Multiclassing Guide.
Practical Examples
Example 1: The “Sorcadin” (Paladin/Sorcerer)
A popular and powerful build combines the martial prowess of a Paladin with the potent spellcasting of a Sorcerer.
- Inputs: Paladin Level 6, Sorcerer Level 6
- Calculation:
- Sorcerer (Full Caster): 6 levels
- Paladin (Half Caster): 6 levels / 2 = 3 levels
- Total Spellcaster Level: 6 + 3 = 9
- Results: A 9th-level spellcaster has 4x 1st-level, 3x 2nd-level, 3x 3rd-level, 3x 4th-level, and 1x 5th-level spell slots. These slots can be used for Sorcerer spells or for Paladin’s Divine Smite.
Example 2: The Arcane Spellsword (Fighter/Wizard)
This build mixes the fighting style of an Eldritch Knight with the vast spellbook of a Wizard.
- Inputs: Fighter (Eldritch Knight) Level 7, Wizard Level 5
- Calculation:
- Wizard (Full Caster): 5 levels
- Eldritch Knight (Third Caster): 7 levels / 3 = 2.33, rounded down to 2 levels
- Total Spellcaster Level: 5 + 2 = 7
- Results: A 7th-level spellcaster has 4x 1st-level, 3x 2nd-level, 3x 3rd-level, and 1x 4th-level spell slots. This build gets access to powerful 4th-level spells like Haste or Fireball while retaining strong martial abilities. For more build ideas, check our guide to the best Baldur’s Gate 3 spell combos.
How to Use This BG3 Spell Slot Calculator
Using this calculator is a straightforward process to help you plan your character’s progression:
- Enter Class Levels: For each spellcasting class you plan to use in your multiclass build, enter the number of levels you will take. If you are not taking levels in a class, leave it at 0.
- Check Total Level: As you enter values, the “Total Character Level” display will update. Ensure this number does not exceed 12, as that is the maximum character level in Baldur’s Gate 3. An error message will appear if you go over.
- Review Spellcaster Level: The “Total Spellcaster Level” is the primary result of the calculation. This single number is what the game uses to determine your spell slot progression.
- Interpret the Results: The tables will automatically update to show your resources. The “Spellcasting Slots” table shows your shared pool of spell slots that recover on a long rest. The “Warlock Pact Magic” table shows your Warlock-specific slots, which are separate and recover on a short rest.
- Reset and Experiment: Use the “Reset” button to clear all inputs and start over. Experiment with different level distributions to see how it impacts your access to higher-level spells. Curious about how Warlocks differ? Read our analysis on BG3 Warlock spell slots.
Key Factors That Affect Spell Slots
- Class Choice: The most significant factor. Full casters contribute far more to your spellcaster level than half or third casters.
- Level Distribution: A 6/6 split between two full casters results in a 12th-level caster. A 6/6 split between a full and half caster results in only a 9th-level caster (6 + 6/2).
- Rounding Rules: The game always rounds down when calculating the contribution from half and third casters. This means a single level in Paladin or two levels in Eldritch Knight give you zero spellcasting progression. You must take 2 levels in a half-caster or 3 in a third-caster to see any benefit.
- Warlock Pact Magic: Warlock levels do not add to your main spell slot pool. This can be powerful, as it gives you a separate, short-rest-recharging pool of high-level slots, but it delays progression on the main spell slot table. See our guide to multiclassing a Warlock for more info.
- Character Level Cap: With a max level of 12 in BG3, every level choice matters. You cannot create the high-level multiclass builds possible in tabletop D&D, making efficient use of this bg3 spell slot calculator even more critical.
- Ignoring Non-Casters: Levels in Barbarian, Monk, and non-subclass Fighter/Rogue do not contribute at all to spell slot progression.
Frequently Asked Questions (FAQ)
- 1. Why are Warlock spell slots calculated separately?
- Warlocks in Baldur’s Gate 3 (and D&D 5e) use a unique system called Pact Magic, not the Spellcasting feature. Their slots are fewer, always at the highest level they can cast, and recharge on a short rest. The two systems are kept separate when multiclassing.
- 2. What does “rounding down” mean for my build?
- It means you lose fractions. A Paladin 5 / Sorcerer 1 has a spellcaster level of 3 (1 from Sorcerer + 2 from Paladin (5/2=2.5, rounded down to 2)). That single lost half-level can be the difference between getting 3rd-level spells and being stuck with 2nd-level ones.
- 3. Can I use this calculator for a single-class character?
- Yes. Simply enter 12 for any single full caster (like Wizard) and leave the rest at 0. The calculator will show you the standard spell slot progression for that class.
- 4. Why do I have spell slots for a level I can’t cast spells at?
- This is a common outcome of multiclassing. For example, a Ranger 5 / Cleric 1 is a 3rd-level spellcaster with 2nd-level slots, but neither class has learned 2nd-level spells yet. You can use these higher-level slots to “upcast” your 1st-level spells for greater effect.
- 5. Does this calculator work for the tabletop D&D 5e game?
- Yes, the multiclassing rules in Baldur’s Gate 3 are a direct implementation of the Dungeons & Dragons 5th Edition rules, so this calculator is accurate for both games.
- 6. Is there a difference in BG3’s multiclassing rules compared to tabletop D&D?
- The core formula is the same. However, one key difference noted by the community is that in BG3, half-caster levels may round up instead of down, which is a slight buff. This calculator uses the official “round down” rule, which is the safest assumption for planning. Warlock slots are also strictly separate in BG3.
- 7. How do I know which spells to pick for my multiclass character?
- You prepare or know spells for each class individually, as if you were single-classed in it. A Wizard 5 / Cleric 3 prepares spells as a 5th-level Wizard AND as a 3rd-level Cleric. Your shared slots can be used to cast any of them.
- 8. Can I use Warlock Pact Magic slots to cast my Sorcerer spells?
- Yes. In BG3, while the slot pools are separate, you can use Pact Magic slots to cast spells from other classes, and vice versa. The game often prioritizes using the ‘native’ slot type first, which can be buggy with reactions.