I've been wondering whether in Harry Potter canon there is any hint on whether there is energy expenditure involved in doing magic. Hints would be things like increased tiredness, fatigue after doing several spells, the need to eat more, etc.

  • I'd have to go back and check , but in the big final battle, is there any hint that Hogwarts defenses waver because the wizards holding them are getting tired? That would be the first place I'd check :)
    – KutuluMike
    Commented Aug 12, 2015 at 12:01
  • In "Goblet of Fire", when Harry was practicing Accio, he was exhausted after his long training session. That's the first example that comes to my mind.
    – Joe White
    Commented Aug 12, 2015 at 13:01
  • But we also have to consider that waving a wand, hand extended, doing precise motions with the wrist as well as bold movements with entire forearm can be tiring on it's own. Same with Hogwarts defences - if, in order to keep pumping the spell they needed to extend their hand there is nothing magical in their exhaustion.
    – Deltharis
    Commented Aug 12, 2015 at 13:37
  • It certainly was exhausting for Harry to maintain the Priori Incantatem connection with Voldemort’s wand in the graveyard at Little Hangleton—the ‘ghosts’ tell him to let go when he feels like he couldn’t have held on for another moment in any case. Commented Aug 12, 2015 at 13:48
  • 1
    @Deltharis, it's like playing Wii tennis. Looks easy, but easily exhausting over extended periods of time. Commented Aug 12, 2015 at 14:03

1 Answer 1


Yes, in as much as concentration and physical activity tire a person. Harry is shown to be exhausted on several occasions when practicing the Accio charm, practicing legilimancy with Snape, and attempting to create a patronus with Lupin.

However, these appear to be the "regular" type of tired: the same as a person concentrating on driving or undertaking a difficult piece of homework. The magic itself does not seem to be taking any energy from the wizard, just the long hours of concentration and activity.

It's more akin to me spending 6 hours practicing how to solve a Rubik's cube.

I think your question is really asking whether the Witch/Wizard has to "give" any energy to the spell, in the style of spellcasters in, for example, the Eragon series. I'm not aware of any direct example of this in Harry potter: magic does not seem to be manipulation of energy in the Potter universe. Or at least if it is, the source is not the person casting the spell.

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