Wizards have a level from 1 to 4. The higher a Wizard's level, the more powerful they are.

A higher-level Wizard will know more spells than a lower-level Wizard. Similarly, they are able to put more power behind their spells and receive higher bonuses when attempting to cast them, as well as channel more power. There are four Wizard levels. If you're unsure what level any of your Wizards are, refer to the relevant Warhammer Armies book for details.