In order to style a room properly, you must hang chandeliers or pendant lights at the correct height. The correct height to hang a light fixture is dependent on the specific situation.
When hanging a pendant light or chandelier over a dining table, the light fixture should hang so the bottom is approximately 30" above the table. Assuming your table is 30" high, the bottom of your light fixture will be about 60" from the floor. If you move your table out of the way to hang your light fixture, the height may seem very low and will probably bump your head on it. After your table is in place, the light fixture will be at the proper height to provide enough light for dining, however high enough not to get in the way. If you have an oversized fixture, you may wish to hang it a few inches higher so it doesn't seem so overpowering over your head when seated at the table.
When hanging a pendant light or chandelier over a high bar, use the same method as above. Assuming that your countertop is 42" high, add 30", so the bottom of your light fixture should be about 72" from the floor.
If you would like to hang a light fixture over a kitchen island, the bottom of the light fixture should be around 6' from the floor.
Billiard or Pool Table
To hang a light fixture over a billiard or pool table, the bottom of the light fixture should be approximately 32" to 36" over the playing surface.
In a Room
If you have a pendant light or chandelier in an entryway, stairwell, bedroom, bathroom, or any other place where people will walk under it, the bottom of the light fixture should be at least 7' from the floor if not higher.
When hanging a pendant light or chandelier in a room with a very high ceiling (18' high or more), center the light fixture 5' from the ceiling. If you have a large picture window near your light fixture, consider centering the light fixture in the window.