Many lamps today come with the lamp base sold separately from the lampshade.
This is very convenient for creating a lamp that is unique and perfectly suited to your room.
Consider the following points to find the correct sized lampshade for your lamp base.
40% of the Overall Height
The lampshade for a table lamp should be approximately 40% of the overall height of the lamp.
If the lamp with shade attached has an overall height of 20" tall, the lampshade by itself should be approximately 8" tall.
Another way to calculate the size is that the widest part of the lampshade should be 8" larger than the largest part of the lamp base.
Before going shopping, take the measurements of your lamp (or bring your lamp with you).
Most lampshades have their measurements written on the package.
The first measurement needed will be the diameter across the top of the lampshade.
The second measurement needed will be the diameter across the bottom of the lampshade.
The third measurement needed will be the measurement down the size of the lampshade, which will usually be a diagonal measurement from the edge of the upper circle to the edge of the bottom circle.
There are 2 main types of mechanisms for attaching the lampshade to the lamp.
Your lamp will only accept one type of mechanism, so make sure you get the correct one.
You can have a harp, which attaches to the left and right of the base of the light bulb and goes up and eventually combine on top of the bulb where the lampshade attaches with a finial (decorative screw on top of the lampshade). This type is called a washer fit.
The second option for a lampshade is a clip lampshade. These are mainly for smaller lamps where the lampshade clips around the light bulb.
Be cautious of selecting a dark colored lampshade or one with a reflective inside.
Dark colors and reflective insides do not let light go through the shade and may not give you the required light you desire.