The hanging height of any wall decoration should be above all aesthetically pleasing to those who look at it everyday. Consider factors such as ceiling height, the dimensions of the decoration itself and the location of other items in the room when hanging a mirror over a backsplash.
Measure the Counter, Backsplash and Mirror
Countertop height varies by age of construction and also by the room in which the counter is installed. Original cabinets and countertops in older homes are typically slightly shorter than those in new homes, and kitchen countertops are generally higher than bathroom countertops. Use a tape measure to be sure, but most countertops should be within several inches of 3 feet high.
Backsplash height varies widely as well, depending on the material used to construct it as well as personal design preferences. Using a tape measure, determine the height of the backsplash and add that to the measured height of the countertop.
Use a tape measure to get the height and width of the mirror as it will hang on the wall, and record this for reference later in the job.
Perform a Test
Interior decorating guidelines suggest hanging all wall art with the center point at 57 inches, which means if your mirror is 2-feet tall, the top of the mirror should be 69 inches from the floor. Using this as a guide, subtract the measurements taken earlier of the counter and backsplash height from 57 inches. That distance will be the height from the top of the backsplash to the center of the picture. Make a light mark on the wall, and ask someone to assist in holding the mirror at that location. Observe the distance from the ceiling, as well as from the backsplash. If the mirror seems too crowded on any side, make a slight adjustment until it looks right.
Hang the Mirror
After a test has been performed to find the right spot, the mirror can be hung using the included hardware. You'll want to hang the mirror according to the included instructions so it is properly supported; large mirrors can be very heavy.
Home improvement stores will have hardware for hanging mirrors without included hardware. Selecting the proper hardware simply requires an approximate weight of the mirror as mirror hanging hardware will be rated for a range of weight between 10 and 15 lbs.
When selecting installation hardware, always overestimate the weight of the mirror. Using hardware that is too strong is better than installing hardware that is not strong enough. Ask for assistance in lifting the mirror, if possible, as mirrors can be quite heavy and break easily. Be as precise as possible in all measurements because slight variations can make the mirror hang uneven on the wall.