CASTER LEVEL
A spell’s power often depends on its caster level, which for most spellcasting characters is equal to your class level in the class you’re using to cast the spell.
You can cast a spell at a lower caster level than normal, but the caster level you choose must be high enough for you to cast the spell in question, and all level-dependent features must be based on the same caster level.
In the event that a class feature, domain granted power, or other special ability provides an adjustment to your caster level, that adjustment applies not only to effects based on caster level (such as range, duration, and damage dealt) but also to your caster level check to overcome your target’s spell resistance and to the caster level used in dispel checks (both the dispel check and the DC of the check).
Caster Level: A spell’s power often depends on caster level, which is defined as the caster’s class level for the purpose of casting a particular spell. A creature with no classes has a caster level equal to its Hit Dice unless otherwise specified. The word “level” in the spell lists that follow always refers to caster level.
No.DM-Rocco said:If you have a Pixie (caster level 8) and you add a level of sorcerer or wizard, would his/her caster level then be 9?
irdeggman said:No CL is not 9.
CL doesn't stack between classes unless it specifically states so.
PHB pg 181
For example a cleric 3 wizard 2 is not a 5th level caster nor does the character have a CL of 5. The character is a 3rd level caster for clerical spells (CL = 3) and a 2nd level caster for wizard spells (CL=2).
Practised Spellcaster feat allows you to add levels of another class to CL (up to 4). {From Complete Arcane}
No.DM-Rocco said:I know about the practiced spell caster feat (thanks for listing it though), but if you had a 1st level Wizard ort a 1 level sorcerer who was a pixie, would that raise her effective caster level to 5, counting her one level of a spell casting class and then her four racial level adjustments?
A spellcasting class is an associated class for a creature that already has the ability to cast spells as a character of the class in question, since the monster’s levels in the spellcasting class stack with its innate spellcasting ability.DM-Rocco said:I understand that a 3rd level/2nd level wizard is not a 5th level caster level, but this is slightly different in that the favored class of the Pixie is sorcerer, so I thought that might influence the effective caster level. I thought I saw that somewhere once.