
It typically consists of an electrically wired base and a screw thread or other mechanism for holding the light bulb. Light bulb standard base sizes Light Bulb Base Type Bulb Base Name Bulb Base Size Screw Bases E5 5 mm E10 10 mm E11 11 mm E12 12 mm E14 14 mm E17 17 mm E26 26 mm E27 27 mm E29 29 mm E39 39 mm E40 40 mm Fluorescent Pin Bases Miniature Bi-Pin 15 mm Medium Bi-Pin 25-26 mm Single Pin 25 mm Recessed Double Contact 25 mm/38 mm 4-Pin – Single-Ended, 4-Pin – 2GX-13 68 mm Axial – Twist and Lock Bases GU10 Pin Spacing 10 mm GX8.5 Pin Spacing 8.5 mm GX10 Pin Spacing 10 mm GU24 Pin Spacing 24 mm Light Bulb Sockets Here is a light bulb base chart that includes pictures of conventional light bulb bases, such as fluorescent bases, LED light bases, automotive light bulb bases, halogen bases, etc., to help you find the light bulb base you have in your hand or need for your light bulb socket. The base of a light bulb also contains information about the bulb type, and wattage, which may also indicate the maximum overall length of the bulb. Light bulb base sizes vary with the type of bulb and application. Additionally, it provides a light bulb base sizes chart and a light bulb socket sizes chart in shareable image format. It broadly covers what the different light or lamp bases mean, why different lamp bases are used for different lighting applications, and where those light bulb bases are used.


This article discusses the different types of light bulb bases and sockets. To fit the bulb socket, light bulbs are made to fulfill these same specifications.

Luckily, there are standards for light bulb base sizes in the lighting industry, and parts are made to meet those standards.
