C9 vs C7 vs mini Christmas lights
C9 bulbs are the large ones for rooflines, C7 are a slightly smaller bulb with a similar look, and mini lights are tiny bulbs for trees, bushes and windows. For a roof edge seen from the street, use C9. For anything you wrap or touch, use mini lights.
The three types compared
| C9 | C7 | Mini (5 mm) | |
|---|---|---|---|
| Bulb size | About 1-1/8 inches across, 2-1/4 inches tall | About 7/8 inch across, 1-1/2 inches tall | About 5 mm (0.2 inch) across |
| Socket base | E17 (intermediate) | E12 (candelabra, nightlight size) | Molded into the strand |
| Typical spacing | 12 or 15 inches | 12 inches or tighter | 2 to 6 inches |
| Seen from | The street and across a yard | Close up and from the driveway | Close up |
| Best for | Roof edges, gables, ridge lines | Smaller houses, porches, garlands | Trees, bushes, windows, wreaths |
| Sold as | 25 ft and 100 ft strings | 25 ft and 50 ft strings | 100 to 400 count, 33 to 133 ft |
| Look | Big, bold, retro | Classic, slightly daintier | Fine, sparkling |
Bulb dimensions are from Christmas Light Source and its C7 and C9 comparison. Spacing and string length vary by brand, so check the package.
C9 for the roofline
C9 is the standard for the roof edge because the bulbs are big enough to read from the street 50 to 100 ft away. A roof edge of 100 ft lit with C9 at 12 inch spacing has about 100 bulbs. Pro installers favor C9 for this reason. See the classic warm-white roofline style.
C9 LED sets use under one watt per bulb, so a whole roofline is a light electrical load. Incandescent C9 bulbs are typically 7 W, and a clear 10 W version is also sold. See LED versus incandescent.
C7 for smaller runs
C7 bulbs are close in look to C9 but a bit smaller. They suit a small house, a porch roof, a garland, or any run where C9 would feel heavy. If you are mixing C9 on the main roof with another area nearby, use one type in each area so the bulb sizes do not clash.
Mini lights for everything you wrap
Mini lights are small and flexible, so they wrap trees, outline windows and fit into wreaths and garlands. A 200-count set is usually 66 ft at 4 inch spacing. They are also the right choice for the front door and for porch posts. On a roof edge they look thin and almost invisible from the street, so use them there only for a subtle modern look. See minimal modern and tree wraps.
Match the base before you buy a replacement
A C7 bulb has an E12 base, the size of a nightlight base, and a C9 has an E17 base. They do not interchange, so pair C7 bulbs with C7 cords and C9 bulbs with C9 cords. Patio-style globe strings often use a bigger E26 base. If you inherit an old C9 cord in good shape, new LED C9 bulbs can go into its E17 sockets (Christmas Light Source), which is a cheap way to upgrade an old roofline.
| Base | Size | Fits |
|---|---|---|
| E12 | Candelabra, about nightlight size | C7 cords and C7 bulbs |
| E17 | Intermediate | C9 cords and C9 bulbs |
| E26 | Medium, the standard household screw base | Patio globe strings; not a C7 or C9 cord |
Which to buy
- Roof edge, any house: C9 in warm white or multicolor.
- Small house or porch roof: C7 or C9, whichever the other lights on the house match.
- Trees, bushes, windows, door: mini lights.
- Eaves with a hanging look: icicle lights, see how many icicle strands.
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Frequently asked questions
What is the difference between C7 and C9 Christmas lights?
Both are larger bulbs with a similar shape. C9 is bigger and brighter, and C7 is a little smaller and more delicate. C9 is the usual choice for rooflines.
Are C9 or mini lights better for a roofline?
C9. They are visible from the street. Mini lights look thin on a roof edge unless you want a subtle line.
How far apart should C9 bulbs be?
12 inches is the most common and gives about one bulb per foot. Some strings are 15 inches apart for a sparser look.
Can I mix C9 and mini lights?
Yes, in different areas: C9 on the roof edge, mini lights on trees, windows and the door. Keep bulb type consistent within each run.
Do C9 bulbs come in LED?
Yes, and LED is the usual choice now. LED C9 uses very little power and runs cool.
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