Rules Index | GM Screen


Mastering Magic / Designing Spells

Duration

Source Ultimate Magic pg. 130
There are no hard-and-fast rules for determining how long a spell should last at a particular level; a weak spell may last hours, while a powerful one may only last a few rounds or be spent in one action. Your best bet is to compare your spell’s effect and duration to those of similar spells of its intended level and spells one level below and above that. Make sure you are fully aware of the differences between “instantaneous” spells and “permanent” spells.