Light Bulb Base Chart

Types of Light Bulb Bases

Find the  light bulb you need using this visual light bulb base chart and detailed illustrations of general light bulb bases, fluorescent bases and specialty halogen base types.

Click Here to Save and Print

Light Bulb base Chart

What is the Difference between Light Bulb Bases?

There are tens of unique bases for light bulbs. The most familiar is the Edison screw base found on most incandescent bulbs and many  halogencompact fluorescent, HID and now LED bulbs.

The common terms are medium, intermediate, candelabra and mogul. However, because the light industry likes mysterious codes, you may also see E26, E12, E39, etc. E obviously is for Edison. The number after the E is the diameter of the base in millimeters (mm).

Here are the most common Edison base names, codes and applications:

Name Code Diameter (mm) Applications
Mogul E39 39 mm
Medium E26 26 mm Common Household Bulbs
Intermediate E17 17 mm Appliances. Old Christmas Lights
Candelabra E12 12 mm Chandeliers. Ceiling Fans.
Mini Candelabra E11 11 mm
Miniature E10 10 mm
Midget E5 5 mm

The large Mogul bases found on higher wattage incandescent and HID bulbs are E39.

Most Edison base bulbs are called "single contact" because there is one contact button at the center of the base. 

Back to blog


Looking for screw in lightbulbs 8mm base colored green or blue


Are there different light bulb base lengths? I’m replacing my candelabra base bulbs and the new one’s, the base is a little longer, and it sticks out a little bit. And it wiggles some even though it’s screwed all the way in. Thanks

James K

I need to replace a tiny light bulb Type E8 .9W Where can I find one in the US Thank you


Hi, I need replacement bulbs for Satco, Halogen excel 39w, 120v, E15China, 530 Lumens.
I hope you can help!

alice breig

looking for Phillips 75 W Reflector R20 Duramax 120v E3 Holland. Or Feit 50 or 75w 130v china. Recessed in kitchen. Led equivalents ok. Dimmer a must. Need 12 or so.

Diane Piercy

Leave a comment

Let us Illuminate your World™