If the mirror is for functioning (ie. not purely decorative), then the center of it should be about 5 feet from the floor.
39 inches or higher.
7 feet
Depending upon the method which the mirror is being hung determines the necessary height. If the mirror is being suspended by a frame a particular point of balance is needed. Overall the center of the mirror needs to be 4-5 feet high.
Since vanity height may vary the actual height of the mirror will vary. The standard for electricians to mount vanity lights is 84". You'll want your mirror height to end to be a few inches below that and the mirror to start right about the backslpash (if this is not a framed mirror).
There is no standard height for hanging a mirror over a mantel. It will depend upon the height of the mantel, the dimensions of the mirror, and the use for which the mirror is intended. If the mirror is intended to be useful for people grooming themselves, it will need to be at a height where they can see at least their shoulders and up. A bottom edge no higher than 1.4m would cater for average adult heights. The height of the top edge should also be considered for this use. It should be a little over the head height of the intended users. A top edge 2m or above would cater for average adult heights. If the mirror is intended to be an item of visual interest in itself, then it can be set at a height that suits the proportions of the mantel height, ceiling height and the size of the mirror. Often, allowing more space abover the mirrror than between the mirror and the mantel looks good. Every situation is different. Check this before hanging the mirror by making a quick paper cut-out the size of the mirror, and trying different positions.
most likely at eye level which is about 5 feet
The height is usually based on the type of mirror that is to be installed above the sink. Take the height of the sink plus the height of the mirror and add 6 inches to find the center for the placement of the fixture junction box. If there is to be a space between the sink and the mirror add that measurement in to factoring of the height.
The minimum height of the mirror should be equal to the height of the man's eyes, which is half of his total height. Therefore, the minimum height of the mirror should be 0.7m.
If these are mounted above a vanity, adjust the mirror height so it doesn't cut off the head of the tallest person in home and is still convenient for putting on makeup.
Head height.
To determine the magnification of a mirror, divide the height of the image by the height of the object. The result will be the magnification factor.
The height of a mirror should be at least half of your height for you to see yourself clearly.