Buying Guide

How to Measure a Lamp Shade

Lamp Shade Measurements
A bell lamp shade on a white background with arrows indicating the top, bottom and slant measurements.

A lamp shade has four different measurements to note before buying. Lamp shade dimensions are typically measured as top x bottom x slant.

  • Top denotes the diameter (or width, if measuring a square lamp shade) of the top of the lamp shade. 
  • Bottom denotes the diameter (or width) of the bottom of the lamp shade. 
  • The slant is the length of the side of the lamp shade.  

When shopping at The Home Depot, all lamp shades are measured by their bottom diameter or width and categorized as mini, small, medium, large and extra large.

How to Measure a Lamp Shade
A measuring tape unfurled on a wood surface.
  • Start by removing the lamp shade from the lamp to make it easier to measure. 
  • Place a measuring tape across the top of the lamp shade, from edge to edge and as close to center as possible, to find the top diameter. Write down this measurement. 
  • If you have a square lamp shade, measure along its width from corner to corner to get the top measurement. 
  • Flip the lamp shade upside down and measure from one edge to the opposite edge across the bottom diameter, just as you did when measuring the top. Write down this measurement. 
  • Flip the lamp shade right-side up. Find the length of the slant by measuring from the top edge of the lamp shade to its bottom edge. The measuring tape should lay flat against the shade’s slope. Write down this measurement. 
  • If you are measuring a square lamp shade with no slant, measure its height from top edge to bottom edge. Use this measurement as your “slant.”  
  • You can also measure the height of the lamp shade by starting at the bottom edge and measuring straight up. The height will be the measurement that is level with the top edge. While not usually a part of a lamp shade’s measurements, knowing the height of a lamp shade will help you pick a shade that best suits your lamp. 
Tips for Choosing a Lamp Shade
A metallic lamp with a simple barrel lamp shade sits next to other home decor on a side table.

Here are a few basic guidelines to help you choose an attractive lamp shade: 

  • The lamp shade’s top diameter should be at least as wide as the base of the lamp. 
  • If you are unsure of what shape lamp shade to choose, match the shape of the lamp shade to the shape of either the lamp or the lamp base. 
  • Simple lamps have more opportunity for experimenting with the lamp shade’s shape, color and style. Ornate lamps are usually best paired with a simple, understated lamp shade. 
  • A good lamp shade will cover all of a lamp’s hardware. 
  • For a balanced look, a table lamp should have a lamp shade that is approximately 2/3 the height of the lamp. A floor lamp should have a lamp shade that is approximately 1/3 the height of the lamp. 
  • You can do away with any design “rule” when you’re looking to break the mold with a striking, contemporary lamp. 
Lamp Shade Materials
A home entryway features a white side table with mirrored doors and a bright red lamp with a simple barrel lamp shade.

Lamp shades come in many different materials but can be sorted into main categories: opaque and translucent.

Opaque lamp shades are often made from silk, thick parchment or laminated card and will direct light in defined beams. They work best for brightening a specific area and highlighting objects.


Translucent lamp shades tend to be the more popular choice in the home. These shades are made from sheer fabric, paper or alternative materials that will allow light to filter through. Translucent lamp shades are great for adding gentle, ambient light to a room. 

Lamp Shade Fittings
A lamp shade with an Uno lamp shade fitting rests on its side.

The fitting on a lamp shade determines how the shade attaches to the lamp. When replacing a lamp shade, you will want to find a new shade with the same type of fitting. There are four main types: clip on fitting, spider fitting, Uno fitting and screw on fitting.

Clip on lamp shades have a wire fitting that attaches directly to the lightbulb. Usually these lamp shades are made for small accent lamps and low-wattage bulbs.

Spider lamp shades are the most common type of fitting. Spider lamp shades attach to the lamp with a finial and a harp that can be easily swapped out for another size to accommodate different lamps. The lamp will usually come with the finial and harp, allowing you to pick the spider lamp shade of your preference.

Uno lamp shades attach directly to the lamp socket without the use of a harp. Uno fittings are sometimes permanently installed, making the lamp shade difficult to replace. A slip Uno fitting, however, is secured underneath the light bulb, allowing you to easily remove and replace the shade. These lamp shades are commonly used for small table lamps and swing-arm lamps.


Screw on lamp shades are another type of removable Uno lamp shade that are also known as a threaded Uno lamp shades. These lamp shades sit above the light bulb and are secured with a screw thread. 

Maximum Light Bulb Wattage
A diagram and a chart show the recommended separation between the bulb and lamp shade and the bulb's maximum wattage.

It is a common misconception that the maximum wattage of a light bulb is determined by the lamp. In fact, the size of the lamp shade determines the maximum wattage of the light bulb. The lamp shade should always be a certain distance away from the light bulb for safety reasons. Check the chart above to ensure you are using the correct wattage light bulb for your lamp shade. 

New lamp shades are an easy, inexpensive way to change your home decor. Now that you know how to properly measure a lamp shade and select the right one for a particular lamp, you can create a big impact with just a tiny change in your home.