A wand is a tool used by wizards and witches to channel magical powers. Most spells are done with the aid of wands. It is possible to do magic without a wand, but is very difficult and requires much concentration and skill. Only advanced wizards can perform spells without the use of wands.[1] Wands are “quasi-sentient”, and as close to animate as an object can get because they are imbued with a great deal of magic.
Although the wand cores may come from the same creature, or the wood may come from the same tree, no two existing wands are exactly alike.
In almost all documented cases, the wand chooses its wizard. This is due to the unique character of each wand, which must match that of the wizard, as the wizard may not be able to perform magic if his and his wand’s characters conflict, or the magic may be sub-par to magic performed with the wizard’s own wand.[3] When trying out different wands, an aspiring wizard may cause some damage when he encounters wands that don’t get along with him.[4] Unfortunately, such trial and error is the only way to find a wand that matches the witch or wizard, and so Mr. Ollivander has become used to his store becoming damaged on a constant basis.
A popular but unconfirmed theory suggests that the wand’s length is directly proportional to the wizard’s height: the longer the wand, the taller the wizard, and the shorter the wand, the shorter the wizard. Examples of this have been found, as in Dolores Umbridge’s short wand, and Ron Weasley’s and Rubeus Hagrid’s long ones. If this is the case it may only be proportionate to the user’s height at the time the wand is purchased, as Draco Malfoy’s wand was shorter then Harry’s but Draco ended up taller then Harry.