Difference between C7 and C9 Christmas Lights

Both C7 and C9 Christmas lights are popular items for Christmas decoration. These lights are used not only inside the house, but on roofs, in yards or on the ground alongside driveways. Both types of Christmas lights can be either semi-transparent, wrapped in the coating through which you can see a bulb, or opaque, which gives a nice colored glow. Both bulbs can also be set in twinkling mode, which gives a festive look to the object they are decorating. There are differences between the two types of bulbs, and we will discuss it in this article.


C7 vs C9 Christmas Lights
Incandescent light bulbs for C7 and C9 Christmas Lights, side to side

C7 Christmas lights use a small base bulb. These bulbs are small and on a small base. The C7 bulbs are normally used for Christmas trees of smaller sizes, indoors or outdoors. C7 Christmas lights are also good for outlining roofs and the edges of a relatively small building.

C9 Christmas lights refer to the C9 bulb they use in their construction. These Christmas lights are suitable for outlining large roofs or a commercial building. When you see a large restaurant, venue, or administrative building outlined with Christmas lights, it is the C9 Christmas lights that are used in decoration.

Comparison chart

C7 Christmas Lights C9 Christmas Lights
Are perfect for retro style decoration Do not fit for retro style decoration
2 inches in length From 2 and ¾ inches to 3 inches in length
Base is E-12 candelabra Base is E-17 intermediate
Incandescent bulbs are 5 or 7 watts Incandescent bulbs are 7 or 9 watts
Not a good option for outdoor tree decoration Perfect for outdoor tree decoration

C7 vs C9 Christmas Lights

What is the difference between C7 and C9 Christmas Lights?

  • If you want to create a retro look for your Christmas tree and home decoration, then your choice is the C7 Christmas light. They are a perfect fit for retro style decoration, unlike C9 Christmas bulbs. It is recommended to use LED bulbs when creating a retro look with the help of C7 Christmas lights. LED is more energy-saving, besides, they are brighter and cooler to the touch.
  • C7 Christmas lights utilize smaller bulbs than C9 Christmas lights. If you need to decorate a larger space, like a two-store home grand facility, you’d better opt for C9 Christmas lights. In general, C7 Christmas lights are used on objects that are not situated too far from the viewer. If you want your decorations seen from far away, go for C9 Christmas bulbs.
  • The base for C7 Christmas light bulbs is E-12 candelabra. C9 Christmas light bulbs, on the other hand, feature a bigger, E-17 intermediate size base.
  • C9 Christmas light bulbs usually come in 5 watts, although some are 7 watts. In LED modification C7 Christmas bulbs are usually 0.96 Watt. C9 Christmas lights, on the other hand, utilize bulbs starting from 7 watts and up to 9 watts. In LED format the bulbs go also as 0.96 watts.
  • If you are thinking about decorating outdoor trees in your backyard, consider using C9 Christmas lights. They look better on outdoor trees than C7 Christmas lights due to their larger size.


In this video you can see a presentation that explains the differences between C7 and C9 Christmas Lights: