Thank you for your question, but this was previously asked and answered.
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From your PC there is a green More info button which will reveal all the questions asked before. For your convenience I have included the answer to your question below:

I place sconces based on their size (height) and where the bulb is on
the fixture, I like the bulb to be placed 63" - 66" above the floor, or
eye level so the sconce adequately lights the face. I do not recall
what the exact dimension is in the photo above, but based on my above
comment, it is irrelevant because you should consider the fixture you
have selected. Start with the bulb height at eye level, then come down
to the plate location. There is no standard where one placement height
fits all, every fixture is different.