A Guide to Christmas Light Bulb Size Chart

What size are Christmas light bulbs? With all the different colors, shapes, wattages, base types, and sizes available, it might seem like you need a master’s degree simply to choose the right bulb sizes for Christmas. With our Christmas light bulb size charts and series guide, we will examine some of the most often used light bulbs and provide you with the information you need to solve the lighting puzzle and identify the product you want.  

Christmas Light Bulb Size Chart  



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Christmas bulbs come in various sizes, such as C3, C6, C7, and C9. The letter “C” stands for Cone, which is the nearly sharp form most often associated with Christmas lights. C7, C9, and C6 bulbs are typical, with C5 and C3 bulbs being used to a lesser degree. The number after the C signifies the diameter divided by 8. 

C3 Bulb:

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C3 bulbs are the smallest of C-series bulbs, measuring around 1/2-inch in diameter and 4/5-inch in height.

C6 Bulb:

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C6 lights are the smallest strawberry-shaped lights, which many people regard to be the “classic Christmas bulb” form. The bulbs are about 3/4 inch in diameter and 1 1/8 inch in height. 

C7 Bulb: 



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C7 lights are somewhat bigger than C6 lights and feature the same strawberry shape. They are 1 1/2 inches tall and 1 inch in diameter. Their breadth lends them a rounded, bulbous appearance.

C9 Bulb:



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C9 lights are somewhat bigger than C7 and feature the same typical strawberry shape as C6 and C7. C9 lights have a diameter of 1 1/4 inch and a height of 2 1/2 inch. 

C9 light wattage may be up to twice as strong as C7 light wattage. They are typically utilized for business applications because to their power, and they truly brighten roofs and bigger portions of your landscape.  

G12 Bulb:



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G Series are globe-shaped lights that come in a range of sizes. The number after the G denotes the bulb’s maximum diameter in eighths of an inch. Simply take the number following the G, split it by 8, then round to the closest inch to get the approximate diameter. G25, for example, is a globe-shaped bulb with a diameter of almost 3 inches, while G15 is a globe-shaped bulb with a diameter of about 2 inches.

Globe (G) bulbs range in size from tiny golf-ball-sized light bulbs for compact, enclosed installations to extra-large globes the size of a crystal ball made to be exhibited. Larger G light bulbs often include carbon or LED filaments, which give them an aesthetically pleasing appearance. Because of the wide range of sizes available, they are simple to fit in a number of fittings in a variety of contexts, including: 

Fixtures with small enclosures 

Pendant lights 


Fixtures for decoration 


Other Commonly Used G Series Bulbs Size Chart

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Incandescent Christmas Lights or LED Christmas Lights

To conclude, an LED string will use less electricity but will burn less brightly. Incandescent lights may produce a lot of heat. Just be careful with this choice since it may become really hot. 

Whether you choose LED Christmas Light bulbs or incandescent bulbs, they will all fit into the same string as long as the sizes match. This is useful if you want to try out both bulb kinds to determine which one you like.

More to Read:

How to Install Smart LED Bulb 

E26 vs A19 – What’s the Difference

Light Bulb Base Sizes Chart, an Easy Guide

Best Smart LED Christmas Light Ideas to Take Home

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Hassan Usmani

Yeelight Tech Expert & Blogger

Hassan Usmani is a former smart home enthusiast, keen to study the linkage between optics and smart home. Yeelight is his favorite brand. He has published hundreds of blogs used in optics and smart home.

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