Replacing a lampshade is an easy and inexpensive way to update the decor of an entire room. Changing the style, fabric or colour of a lamp can accent different aspects of a room, or even change the use of the lamp itself from an accent to a main lighting component, or from a bright reading lamp to one that gives off softer light. Fitting a new lampshade requires having two pieces of information: the measurements of the shade and the type of fitter, or attachment, used to secure the lampshade to the lamp.
Remove the existing lampshade from the lamp, and use the measuring tape to measure the lampshade's width across the top, width across the bottom and height down the side. Most lampshades are fitted, in inches, using the measurements of the top width by the bottom width by the side height.
Measure the length from the top of the lamp's harp, or metal wire piece on which the lampshade rests, to the bottom of the socket (where the light bulb fits) if you do not have an existing lampshade. This height will help you make sure a replacement shade fits your lamp.
Determine the type of lamp fitter required for your lampshade. There are a number of types of fitters which connect a lampshade to a lamp. These include harp/spider fitters, which use a finial, or ornamental top piece which usually screws on the top of the shade to secure it; slip UNO fitters, which sit on the socket and are secured by the light bulb; or threaded UNO fitters, for light bulbs that orient downwards and are secured by a separate screw.
Purchase and install a replacement lampshade and the correct fitter type using the measurements you took.