Standard Light Bulb Base Sizes

It s referred to as having a medium or standard base.

Standard light bulb base sizes.

The first letter designates the shape or form of the base and the number represents the width of the base normally in millimeters. It s used for nightlight bulbs and sometimes for decorative light bulbs used in chandeliers and over bathroom mirrors. The most commonly used a series light bulb type is an a19 bulb or its metric iec equivalent the a60 bulb which is 19 8 in 2 3 8 in. 1 888 455 2800 fax 1 508 363 2900.

Unlike the light bulb shapes the number in the light bulb base measures the light bulb base diameter in millimeters. They are commonly used for general lighting in standard light fixtures such as ceiling lights lamps can lights outdoor spotlight and flood light fixtures and vanity lights. Other sizes with a data sheet in iec 60064 are a50 a55 a67 a68 a71 a75 and a80. Shoppers of led light bulbs often confuse the specifications for base type e26 or e27 and bulb shape a19.

E26 is the size of most light bulbs used in the u s. Common bulbs with e26 e27 bases. The candelabra e12 has a diameter of 12 millimeters. Most common light bulb uses including lamps recessed flush mount flood lights are going to have one of the first three base types shown above.

Screw bases come in several sizes and they are referred to by both a descriptive name and size. From top left to bottom right. Standard arbitrary a bulbs are the most widely used and thought of when it comes to household lighting. A further explanation of the light bulb base sizes you can look at the letter number references e12 e17 and e26 to help understand a bulbs base style and size.

Look at your fixture to determine its base type. E12 is the smaller candelabra base. Pin type bases are normally used for track lighting landscape bulbs. Bulbs with these base types are available in many different styles.

Look at your fixture to determine its base type. A19 led filament bulbs in ceiling fan fixture a21 led bulbs in bedroom lamps a19 gold tint led filament bulb in porch light fixture a19 led fireworks bulbs in string lights. Fluorescent pin bases miniature bipin medium bipin single pin recessed double contact 4 pin single ended 4 pin 2gx 13 axial twist lock bases 10mm gu10 10mm gx10 24mm gu24 bi pin bases 4mm g4 4mm gu4 4mm gz4 5 3mm g5 3 5mm g5 5 3mm gu5 3 5 3mm gx5 3 5 3mm gy5 3 6 35mm g6 35 6 35mm gy6 35 6 35mm gz6 35 8mm gy8 8 5mm g8 5 9mm g9 9mm g9 pin. 60 mm wide at its widest point and approximately 4 3 8 inches 110 mm in length.

E17 intermediate base is in between these two sizes.