When casting a spell at a lower caster level, do you have to make that decision when you prepare the spell or when you cast it?

Question

Its a rarely used ability, but spell casters have the ability to cast spells at a lower caster level provided that they still meet a spell's minimum requirements.

When is this choice made for prepared spell casters? Is it when they prepare the spell or as they are casting the spell?

Caster Level

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.

Answer 1

A caster probably picks the spell's caster level when the spell comes into effect

Casting Time says, "You make all pertinent decisions about a spell (range, target, area, effect, version, and so forth) when the spell comes into effect." Absent rules to the contrary, this GM has always assumed picking the spell's caster level is also a "pertinent decision."