Light bulb Size : What are the different and standard bulb sizes?
Light bulbs come in several varieties of shapes, sizes and standard wattages. Before buying a light bulb, it’s important to understand which type will be suitable for your home or business and how much illumination is required. Light bulb size is expressed by a combination of letters and numbers. The letter is the series, the numbers indicate the diameter of the bulb shape. The most commonly used household bulb is the A-19 (in US) or A-60 (UK bulb sizing). The bulb is “A” type and the diameter would be 2 3/8″
Where can I find out the light bulb size I need?
A bulb’s code number is made up of a letter or letters followed by a number. The letter represents the bulb’s shape, and the number represents its diameter in eighths of an inch. The A-19 is the most commonly used household bulb. The light bulb is “A” type, with a diameter of 23/8″. A 65BR40 is a 5 watt reflector with a power rating of 65 watts “in circumference.
Jump immediately to the FAQ section of this page
Table of Content
- How do I find the light bulb size I need?
- Light Bulb Size Chart and Series
- Most Popular Light Bulb Sizes (US and UK)
- Light Bulbs Replacement Guide (video)
- Light Bulb Sizes – Shapes, and Codes
- Light Bulb Size Explained (video)
- FAQ
- Conclusion on light bulb sizes
Related: Looking for light shade sizes? check here, Understanding Light Bulb Base sizing? Read all about it here
In fact, there are different types of lighting such as track lighting, night lights, landscape lighting, decorative lighting, garden lighting, residential lighting, hard-edged lighting, and more.
Light Bulb Size Chart and Series
We must understand that the light bulb series shows the shape and a number code shows the light bulb diameter in 1/8th inch and millimeters (mm). The type of bulb is the determinant. Our size charts will be organized via various sizes, bases, type of light, and intended use.
Most Popular Light Bulb Sizes (US and UK)
Check the below table with Light bulb series, the code of the most popular or standard light bulb in US and UK and the dimensions.
Are US and UK light bulbs the same?
No they are not the same. In the U.K. they are designed to run on 240v whereas in the US, they run on 120v.
| BULB series | CODE | DIAMETER IN (Inches and mm) | LENGTHS IN (inches and mm) |
| A Series | A19 (US) or A6 (UK) | 60 mm 2.4 inches | 3.9 – 4.3 inches (99.06 – 110 mm) |
| B Series | B10 | 31.75 mm 1.3 inches | 3.5 – 4.4 inches (90 -113 mm) |
| C Series | C9 | 28.58 mm 1.1 inches | 3.5 – 3.9 inches (90 – 100 mm) |
| CA Series | CA10 | 31.75 mm 1.3 inches | 3.5 – 3.9 inches (90 – 100 mm) |
| R Series | R50 | 159 mm 6.3 inches | 3.4 inches (86 – 87 mm) |
| R Series | R63 | 200 mm 7.9 inches | 3.9 – 4.0 inches (100 – 102 mm) |
| R/BR Series | R80 | 254 mm 10 inches | 4.4 – 4.8 inches (112 – 118 mm) |
| PAR Series | PAR16 | 50.8 mm 2 inches | 2.0 – 2.2 inches (50 – 55 mm) |
| PAR Series | PAR20 | 63.5 mm 2.5 inches | 2.5 – 8.9 inches(64 -89 mm) |
| AR Series | PAR36 | 111 mm 4.4 inches | 2.3 – 2.6 inches (58 – 66 mm) |
| PAR Series | PAR36 | 120.65 mm 4.8 inches | 5.3 – 5.4 inches (134 – 136 mm) |
| MR Series | MR11 | 35 mm 1.4 inches | 1.5 – 1.7 inches (37 42 mm) |
| MR Series | MR16 | 50.8 mm 2 inches | 1.8 – 2.1 inches (45 – 53 mm) |
| G Series | G25 (US) or G80 (UK) | 80 mm 3.2 inches | 120 mm 4.7 inches |
| G Series | G30 (US) or G95 (UK) | 95 mm 3.7 inches | 140 mm 5.5 inches |
| G Series | G40 (US) or G125 (UK) | 125 mm 4.9 inches | 6.5 – 6.7 inches(165 – 170 mm) |
| T Series | T30 | 30 mm 1.2 inches | 8.9 – 11.8 inches (225 – 300 mm) |
| T Series | T45 | 45 mm 1.8 inches | 110 mm 4.3 inches |
| T Series | T5 | 16 mm 0.6 inches | 12.0 – 57.6 inches (305 -1463 mm) |
| T Series | T8 | 26 mm 1.0 inches | 13.0 – 48.0 inches (330 – 1220 mm) |
Light Bulbs Replacement Guide (video)
Light Bulb Sizes – Shapes, and Codes
A Series.
They can be called Standard bulbs, general lamp service (GLS), or arbitrary and typically used at home. The A-Series traditional bulbs are used as kitchen lamps, porch lamps, ceiling lamps, floor and table lamps, and reading lamps.
The A Series is popular due to its light bulb shapes and smart bulbs. The bulbs are used with base types screw (E27, E14) or bayonet (B22) and have a wide range of uses.
| A19 or A60 Light Bulb Size Chart | |
| Common Lengths in inches and mm | 3.9 – 4.3 inches (100 – 110 mm) |
| Diameter in mm and inches | 60 mm (2.3622 inches) |
| Light bulb code | A19 (US) or A60 (UK) |
| Diameter 1/8th inch | 2 3/8″ (10 / 8 diameter) |
A-series bulb types
- Halogen bulbs
- Incandescent Lights
- Compact Fluorescent
- LED Filament Bulbs
B/C/CA Series
We start by understanding what the B/C/CA series stands for:
B – Blunt
C – Conical or Candle
CA – Candle Angular
They usually produce light similar to the candle flames., however, they are smaller in size compared to other types of bulbs. They come in different candle bulb shapes, for example, CA is similar to candle flames with a curved tip, C and B are stylized and blunted. They are used for holiday lighting, artificial candles, chandeliers, decorative events, and night lighting.
Some common B, C, and CA types include light bulb bases like E27, B22, B15, SES14, and CES12.
| Common B, C, and CA | |||
| Light Bulb Code | B10 | C9 | CA10 |
| Common Lengths in mm and inches | 90 – 113 mm 3.5 – 4.4 inches | 90-100 mm 3.5 – 3.9 inches | 110-130 mm 4.3 – 5.1 inches |
| Diameter in mm and inches | 31.75 mm 1.3 inches | 28.58 mm 1.1 inches | 31.75 mm 1.3 inches |
| Diameter in 1/8th inch | 10/8 (1 1/4″) | 9/8 (1 1/8″) | 10/8 (1 1/4″) |
R and BR Series
Let us start by understanding what R and BR series stands for:
R – Reflector
BR – Bulged Reflector
They are commonly used as security lights, track lights, display lights, smart bulbs or recessed lights.
They produce a wide beam angle ideal for residential and commercial settings.
| Common R/BR Series | |||
| Light Bulb Code | R50 | R63 | R80 |
| Common Lengths in mm and inches | 86 – 87 mm 3.4 inches | 100 – 102 mm 3.9 – 4.0 inches | 112 – 118 mm 4.4 – 4.6 inches |
| Diameter in mm and inches | 159 mm 6.3 inches | 200 mm 7.9 inches | 254 mm 10 inches |
| Diameter in 1/8th inch | 50/8 (6 1/4″) | 63/8 (7.86″) | 80/8 (10″) |
MR Series.
MR stands for Multifaceted Reflector are larger than the other light bulbs discussed above. They have a multi-faceted reflective lining. Their base typesGU4, GX5.3, and GU10.
The fact that they are multi-faceted makes them produce directional beams of light. They also emit narrow or wide spotlights.
They are commonly used for landscape lighting, desk lamps, track lighting, display cases, and recessed lighting.
| Common MR Series Bulbs Size Chart | ||
| Light bulb code | MR11 | MR11 |
| Common Lengths in mm and inches | 50 – 55 mm 2.0 – 2.2 inches | 64 – 89 mm 2.5 – 8.9 inches |
| Diameter in mm and inches | 50.8 mm 2 inches | 63.5 mm 2.5 inches |
| Diameter in 1/8th inch | 16/8 (2”) | 20/8 (2.5”) |
G Series
G series means Globe series bulbs. They come in a wide range of sizes and are mostly spherical. There are small G series bulbs with enclosed fixtures. The Large G has carbon or LED filaments, making them look appealing to the eye. They can fit in different settings such as pendant lamps, vanities, small enclosed fixtures, decorative fixtures, and chandeliers.
| Common G Series Bulbs Size Chart | ||
| Light bulb code | G25 (US) or G80 (UK) | G30 (US) or G95 (UK) |
| Common Lengths in mm and inches | 120 mm 4.7 inches | 140 mm 5.5 inches |
| Diameter in mm and inches | 80 mm 3.1 inches | 95 mm 3.7 inches |
| Diameter in 1/8th inch | 25/8 (3.14”) | 30/8 (3.70”) |
T Series
T Series stands for Tube or Tubular bulbs and comes in various sizes and shapes. The fluorescent tubes are similar to test tubes. Their light bulb base sizes include G13, G5, E12, and E27. They are mostly used for garage lighting, pendant lamps, chandeliers, warehouse lighting, sconces, and chandeliers.
| Common T Bulb Size Chart | ||
| Light Bulb Code | T30 | T45 |
| Common Lengths in mm and inches | 225 – 300 mm 8.9 – 11.8 inches | 110 mm 4.3 inches |
| Diameter in mm and inches | 30 mm 1.2 inches | 45 mm 1.8 inches |
| Diameter in 1/8th inch | (1.18”) | (1.77”) |
AR and PAR Series
Let’s start by understanding what AR and PAR series stands for:
AR – Aluminum-faceted Reflectors
PAR – Parabolic Aluminized Reflectors
The AR and PAR series range base types include B22, E27, E14, G53, G12, and GU10, which are ideal for commercial and residential settings. They are mostly used as architectural and landscaping lights, recessed lights, decorative floodlights, track lights, and security lights.
AR and PAR series have reflective materials and are shorter than R and BR, making them fit for light fixtures.
| Common AR and PAR Series | ||
| Light Bulb Code | PAR16 | PAR20 |
| Common Lengths in mm and inches | 50 – 55 mm 2.0 – 2.2 inches | 64 – 89 mm 2.5 – 3.5 inches |
| Diameter in mm and inches | 50.8 mm 2 inches | 63.5 mm 2.5 inches |
| Diameter in 1/8th inch | 16/8 (2″) | 20/8 (2.5″) |
Light Bulb Size Explained (video)
Frequently Asked Questions (FAQ)
What is the most popular Light bulb size?
The A19 (US) or A60 (UK) is the most standard light bulb size. (other Type A Light Bulbs like A15, A19, A21 & A25 are also common sizes) These lamps fit medium screw bases (E26 and E27) or the candelabra base (E12).
| Light bulb |  |
| Light bulb code | A60 (UK) or A19 (US) |
| Diameter in millimeters | 60mm |
| Diameter in one-eights of an inch | 19/8 (2 3/8″ diameter) |
| Length in mm and inches | 100-110mm (3.9-4.3 inches) |
Conclusion on light bulb sizes
Having an illuminating bulb in your living room could be fun and aesthetic. As discussed in this light bulb size chart guide, there are different types of lighting. You will discover that different lightings or bulbs serve different purposes and come in different shapes and sizes.
Choosing the right bulb is upon you based on the purpose intended. You also need to ensure that the quality is great and perfect.
If you enjoyed reading this sizing guide, please don’t hesitate to leave a comment below!
Picture in this post by Patrick Tomasso on Unsplash
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I’m looking for small filament replacement bulbs with markings:
DB
S 67
Do you have such a bulb? What would be the cost? I would need about six bulbs.
Hello Glenn, thanks for reaching out. We’re not a shop, but an informational site specialized in expert reviews on size-charts. In this case Light bulb sizes. I believe the most easy way to find the light bulb is at amazon? (link here) Have a nice day!