When choosing a shade for a lamp base, take the time to measure the base to ensure the shade you select is the proper fit. If you don't do this properly, the lamp shade will not be in proper proportion to the lamp base and the lamp will not look right in your home.
Measure the lamp from the bottom of the base to bottom of the socket cap. The shade's bottom diameter should be the same as this measurement.
Notice the height of the harp. The harp is the support that attaches the shade to the lamp. The height of the lampshade is related to the harp height. The shade height should be approximately the same as the harp height.
Choose a shade with a bottom diameter within 2 inches of the lamp height and a height that is roughly the same as the harp height.