Measure the lamp base height from the bottom of the base to the top of the socket
Measure the widest part of the lamp base
Choose a lampshade height that is about two-thirds the height of the lamp base
Choose a lampshade bottom diameter that is about twice the widest part of the lamp base
Make sure the lampshade top diameter is smaller than the bottom diameter for a balanced look
Ensure the shade covers the socket and harp hardware
Check that the bottom of the shade sits above the lamp base by a few inches
Use a taller shade for tall, narrow lamps
Use a wider shade for short, broad lamps
Match the shade size to the room and table size
Verify the bulb does not touch the shade
Confirm the shade allows enough light for the intended use