Question: I saw in a [recent answer](https://rpg.stackexchange.com/a/152447/15689) a reference to 1/3 casters and 1/2 casters, and have never encountered this terminology before:

> 
> Paladin's are known as 1/2 casters, so their spell progression isn't as big as full casters. 
> 
> 
> 

What does it mean to be a 1/3 caster vs a 1/2 caster vs a full caster? How does one distinguish between the three, and which classes correspond to which types of caster?

Answer: 
It refers to the speed at which classes gain spell slots and new levels of spells during their progression. Full casters (like a Wizard) gain spell slots fastest, while 1/3rd casters only gain slots and new spell levels at about a third that rate.

The name "1/2 caster" and "1/3 caster" comes from the Multiclassing rules, which state that if you have levels in multiple classes capable of casting spells, you use a specific table to determine your spell slots. You only get to add half and a third of the levels in those classes (rounded down) to determine your total spell slots.

You can read more about this in the PHB on page 164, under the header "Spellcasting".

Note that these terms only refer to classes that have the **Spellcasting** class feature. Classes that cast spells through a different system (like a Warlock or 4 Elements Monk) don't have a caster progression and don't stack with levels in other classes when multiclassing.

For a list of classes:

### Full casters

* Bard
* Cleric
* Druid
* Sorceror
* Wizard

### Half casters

* Paladin
* Ranger

### Third casters

* Eldritch Knight Fighters
* Arcane Trickster Rogues
The fractions here come from the multiclassing rules: when figuring out what level of “multiclassed spellcaster” you are, in order to figure out your spell slots, you need to add your full level in some classes (like wizard), half your level in other classes (like paladin), and a third of your level in yet other classes (like arcane trickster). These fractions roughly correspond to how much spellcasting those classes actually give: wizards and other “1” classes get 9th-level spells, paladins and other “½” classes get 5th-level spells, and arcane tricksters and other “⅓” classes get 4th-level spells.