Introducing Typical Bulb Shapes and Sizes

April 15, 2022

LED Light bulbs come in a variety of shapes and sizes. They use the same shapes as traditional bulbs but provide less power consumption and longer lifetime. There are typically six different bulb styles people usually use at home, and each style is designed for specific lighting applications and scenarios. Let’s take a look at these common types and sizes and understand which is needed for a required scenario.

A Series Light Bulbs (Arbitrary)

A Series Bulb

A type light bulbs/A-series light bulbs are the most common bulb types, which have the conventional look of what people refer to as Edison bulbs. An A Series bulb has a pear-like shape and is typically fitted to an Edison screw base. An A bulb, according to IEC TR 60887:2010 definition, have “a spherical end section that is joined to the neck by a radius that a) has a centre outside the bulb, b) has a magnitude greater than the radius of the spherical section, c) and is tangent to both the neck and the curve of the spherical end section.”.

The number that follows the “A” designation indicates the bulb’s diameter, either in one-eighth inch units (in the US) or in millimeters. For instance:

A14 bulb: 14/8 = 1-6/8” diameter

A19 bulb: 19/8 = 2-3/8” diameter

A60 bulb: 60mm diameter


This (General Lighting Service) GLS light bulb is ideal for most household settings, such as ceiling lights, lamps, closet lights, kitchen lights, as well as lighting for workplaces, restaurants, hotels, and bars!

BR Series Light Bulb (Bulged Reflector)


BR light bulbs are descendants of R-shape bulbs. However, the “Bulged Reflector” bulb includes an extra reflector in the neck of the bulb to better capture and cast light forward. This extra reflector in the neck creates a “bulge” before the socket base begins.

BR-series bulbs are considered as directional flood lights, which means that they provide more than 45° (normally 120°) angle when lighting up an area. This helps to light up a broad area in a room or to create a wall-washing effect. BR bulbs are longer than PAR bulbs and also produce less shadows compared to PAR bulbs.

The number that follows the “BR” indicates the bulb’s diameter in one-eighths of an inch.


BR light bulbs provide the best wide-angle illumination, and are typically used in applications where a broad pattern of ambient light is needed such as recessed lights, display lights, track lights or can lights.

C Series Light Bulb (Candle or Conical)

C Series Candle Bulb-1
C Series Candle Bulb-2

C shaped bulbs are also known as Candelabra light bulbs. They are defined as light bulbs “consisting of a conical or near-conical end section, which is joined at the neck by an approximately hemispherical section” with a bulged base that leads to a round or pointed end. Some bulbs are bent at the end, thus presenting a flickering flame effect.

The number is the diameter of the widest part of the lamp in eighths.


C-type light bulbs/C series light bulbs are used as accent lighting and decorative lighting, such as on chandeliers, night lights and string lights. Candle shaped lights are also commonly used in holiday lights, such as Christmas lights!

G Series Light Bulb (Globe)/Type G Light Bulbs (Globe)


G-type light bulbs/G series light bulbs are bulbs of “essentially spherical shape”. These bulbs perform well in fixtures where the globular shape of the bulb can visually spread a wider beam. These bulbs are usually used for decorative scenarios, such as bathroom vanities and chandeliers.

These are decorative bulbs that light up a lot of bathroom vanities.       


G series bulbs can be used for many applications throughout the home, such as wall sconces, kitchen lights, chandeliers, and makeup vanity lights. This globe shaped light also makes them more aesthetically pleasing to use in situations where there is no covering over the light.

MR Series Light Bulb (Multifaceted Reflector or Quartz Reflector)

MR Series MR16
MR series GU10
GU10 / MR20

The MR light bulb is a “curved focusing reflectorized bulb which may have a multifaceted inner surface that is typically dichroic or aluminum coated”. These bulbs are used in many track lights and high end kitchen lamps, and provide focused lighting for things that need to draw attention to, like kitchen islands and dining tables. MR bulbs were originally designed for projectors, but are now more applied in residential lighting and retail lighting.

PAR Series light bulb (Parabolic Aluminized Reflector)

PAR Series Lamp

PAR stands for parabolic aluminized reflector and are bulbs that “formed by the sealing together during the lamp-making process of a pressed glass parabolic reflector section and a pressed glass lends section”. While for LED lamps nowadays, the PAR description is used to define only the shape rather than the materials, as most are not made of glass any more. They have reflective surface to make the light concentrated. PAR bulbs have a parabolic aluminized reflector, serving as a reflective surface, which then redirects the downward light to the front and forms a in a highly concentrated beam.

What’s the difference between BR and PAR light bulbs? Well, the main difference is the beam. BR bulbs tend to be more spread out, whereas the PARs are more focused. Moreover, PAR series bulbs provide more lumen output and are normally higher power bulbs (more watts).

The number that follows the “PAR” indicates the bulb’s diameter in one-eighths of an inch.


PAR series bulbs are ideal for outdoor landscape lighting, track lighting, spotlights as well as indoor applications such as bathroom or kitchen lighting.

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