How to Tell What Kind of Light Bulb You Have

It seems like an easy repair to manage when a light bulb stops functioning. Although that's the case in most situations, there can be times when you don't know what product is providing illumination.

Some light bulbs come with an odd shape, while others might have a base you've never seen before.

If you're unsure of what you have, here are some steps to help you know how to tell what kind of light bulb you have.

1. Know the Source

You can find hundreds of different LED bulb designs that duplicate the look and feel of other technologies. There might be an old incandescent bulb to replace, a unique fluorescent design, or something else.

Since many light bulbs use the same letter and number designations, such as A19, to tell what they are, the result is often more confusion.

Here are some tips to help you know what you've got so that you can find a suitable replacement for the light bulb.

2. Understand the Shape

Several light bulb shapes are available today, with many coming in multiple sizes to consider. Most homes use an A-style bulb with a size designation of 19 or 21. You'll see this information included in the product packaging.

Decorative bulbs have their own letter and number designation. You'll want to be careful when replacing candelabra products because the base sizes can be significantly different.

Some fixtures use R, MR, BR, or PAR light bulbs. These have a flared casing that makes them distinctive.

If you have chandelier bulbs to replace, the tips can be different even when the letter and number designation are the same.

It's always better to try a direct replacement of the same light bulb from the same manufacturer. Check the size and shape for comparison when that isn't possible, or if you want to upgrade to a more energy-efficient product.

Here's a closer look at each shape that could be found in the home.

3. Recognize the Base Size

Most residential light bulbs use a screw-in base. There are different widths, but you can visually see the differences in size.

Some light fixtures use a pin base, especially if you have fluorescent lights to replace.

Here's a closer look at the different designations. It helps to look at the bulb to see if any markings are on it to indicate what you need.

4. Measure the Base Circumference

If you're unsure of the number designation to use for a light bulb that requires replacement, you can measure the base to find the correct product.

All light bulb number designations are based on standard sizing from the product's base circumference.

Each number represents 1/18-inch. That means you can multiply that fixture by the number of lengths found to find the designation you need.

Some light bulb bases are listed in millimeters instead of inches.

If you have an A19 light bulb in the United States, it likely has an E26 base. That indicates it is a screw-type Edison product with a 26 mm diameter. Here are a few examples of what you can find in the marketplace today.

When you're unsure of the bulb size because a direct comparison is difficult, you can measure the circumference. This step is helpful if you don't know if the product requires a 19 or a 20 base in inches since the difference is only 1/8 inches.

5. Ask for Professional Help

If you've followed these steps and are still unsure what light bulb you have, contact our customer service department to receive assistance. Our team will work to get you the answer you need to replace the product that isn't working.

It can be frustrating to need to replace a light bulb and not know the product you need. With the information found in this guide, you'll be able to select the correct item.