E12 is the candelabra base, 12 mm across, used in most multi-arm chandeliers. E26 is the medium base, 26 mm across, used in pendants and larger fixtures. The number is the thread diameter in millimetres.
Match the base first, then the shape, then the look. For a chandelier: 2700K, 90+ CRI, dimmable, and frosted rather than clear if the bulbs are visible from a chair.
Buying bulbs for a chandelier means buying twelve or twenty at once, so getting it wrong is expensive. Here is what the codes mean.
The base: E12 or E26
“E” stands for Edison screw and the number is the outside diameter of the threaded base in millimetres: E12 is 12 mm, about half an inch; E26 is 26 mm, about one inch. Nothing else is encoded there.
A fixture’s sockets are fixed, so this is not a preference. If the arms take E12 and you want E26 output, you need a different fixture. Adapters exist, but they raise the bulb, change the proportions and are usually visible.
Then the shape
Shape codes work the same way: a letter for the profile, a number giving maximum diameter in eighths of an inch. A15 is small, often used in ceiling fans; A19 is the ordinary household bulb; A21 is the larger body for 100W-equivalent and above.
Candelabra fixtures also use torpedo and flame shapes on the same E12 base. If a fixture was designed around a slim candle profile, a squat globe looks wrong even though it fits.
| Base | Typical fixtures | Output per bulb |
|---|---|---|
| E12 candelabra | Multi-arm chandeliers, sconces, small pendants | 350–500 lm (40–60W equiv.) |
| E26 medium | Pendants, flush mounts, single-lamp fixtures | 800–1,600 lm (60–100W equiv.) |
What to specify once the base is settled
Colour temperature: 2700K in a dining room or bedroom, 3000K in kitchens and halls. Never above 3000K over a table — higher Kelvin means more blue and more glare.
CRI: 90 or better, and prefer a maker who publishes an R9 figure. A 90 CRI bulb with R9 under 50 renders red as orange or grey; 95 is the safer target where people eat.
Finish: frosted if you can see the bulbs from a chair — the most effective fix for glare from an exposed-bulb fixture, ahead of changing the hanging height.
Buy them all at once, from one batch. A twenty-light chandelier shows variation between bulbs immediately. Makers bin LEDs by colour, but nothing guarantees consistency between runs bought months apart.
Wattage: the misread number
“Max 60W per socket” is a safety limit, not a recommendation. Twenty sockets at 60W is 1,200W — beyond almost any residential dimmer. With LED, twenty bulbs at 4–5W each is already a lot of light.
Never exceed the fixture’s printed maximum wattage. If the label is missing or the fixture has been rewired, have a licensed electrician confirm its rating. Local electrical code takes precedence.
What to take away
- E12 = 12 mm candelabra; E26 = 26 mm medium. The number is the diameter.
- Base first, shape second, looks third.
- Shape numbers are eighths of an inch: A19 is 19/8 in.
- 2700K, 90+ CRI, dimmable, frosted if the bulbs show.
- Buy the full set together; stay under the max wattage.
More in chandeliers and pendants, or see the size guide.
What is the difference between E12 and E26 bulbs?
The base diameter. E12 threads are 12 mm, used in candelabra sockets; E26 threads are 26 mm, used in standard household sockets. They do not interchange without an adapter.
Can I use an E12 to E26 adapter in a chandelier?
Often it fits, but it lifts the bulb, changes the fixture’s proportions and can push a large bulb past the arm spacing. Match the base instead.
What bulbs are best for a dining room chandelier?
2700K, 90 CRI or better with a published R9, dimmable, frosted if the bulbs are in view. Keep total wattage low — LED candelabra bulbs at 4–5W each are plenty.
Not sure what your fixture takes?
Socket type, count and recommended wattage are on every product page because they are settled in the specification before a piece is built — and a custom piece can be specified around E26 sockets if you need the output.
Explore custom designBase and shape designations follow standard lamp nomenclature. Selection guidance reflects recurring advice in lighting communities.