E26 vs E12 Bulbs: Which Base Does Your Fixture Need?

An E26 bulb is the standard screw-in bulb base used in North America, and an E12 bulb is the smaller candelabra base. If you are replacing a bulb or shopping for a fixture, the base is the first thing to check, because the wrong one simply will not fit. This guide explains what the codes mean, how E26 compares with E12, why the European E27 and E14 sizes are not interchangeable with US sockets, and how to read the label on your fixture.

What is an E26 bulb?

The "E" stands for Edison screw, the threaded design invented in the 1800s. The number is the diameter of the screw thread in millimeters, so an E26 base is 26 mm across. In the United States and Canada it is called the medium base or standard base, and it fits the lamps, ceiling fixtures and pendants found in most homes. If you have ever bought a regular A19 household bulb, it was almost certainly E26.

Typical E26 bulbs include the familiar A19 shape, globe bulbs, and filament-style LED bulbs. Many pendant lights and flush mount ceiling fixtures use one or more E26 sockets, which makes it the easiest base to find in any hardware store.

What is an E12 bulb (candelabra base)?

E12 follows the same logic: a 12 mm screw base. It is called a candelabra base because it was designed for small, candle-shaped bulbs in chandeliers and decorative sconces. You will find E12 in many wall sconces, mini pendants, small chandeliers and nightlights. Common E12 bulb shapes are the B10 and B11 candle (also called torpedo) and the small G14 globe.

Because the base is smaller, E12 bulbs are generally lower in wattage and lumens than E26 bulbs. That makes them well suited to accent and ambient light, but you may need several in a fixture to light a room. Fixtures with multiple arms, such as many chandeliers, usually use E12 for this reason. See our chandeliers to compare how many sockets and which base each design uses.

E26 vs E12: the main differences

• Size: E26 is 26 mm across and E12 is 12 mm, so E26 is a little more than twice as wide.
• Common names: medium base versus candelabra base.
• Typical bulb shapes: A19 and globes for E26, candle and small globes for E12.
• Brightness: E26 bulbs cover the full range of household brightness, while E12 bulbs are mostly for decorative and accent light.
• Where you find them: table lamps, ceiling lights and pendants use E26 most often. Chandeliers, small sconces and decorative fixtures use E12 more often.

The bases are not interchangeable. An E26 bulb will not thread into an E12 socket and vice versa. Adapters exist that convert one size to another, but they can push the bulb outside the shade or exceed the fixture's wattage limit, so use them cautiously.

E26 vs E27: are they the same?

This is one of the most common questions, and an important one if you are buying a fixture from abroad. E27 is the European medium base, 27 mm across, used on 230 V circuits. E26 is the North American version, used on 120 V circuits. The two sizes are so close that they can often be physically screwed into each other's sockets, but they are not designed to be mixed:

• Voltage: an E27 bulb made for 230 V will not run correctly on a 120 V US circuit, and a 120 V bulb in a 230 V socket can fail or become a hazard.
• Tolerances: the thread dimensions differ slightly, so a bulb may sit loosely, or contact may be poor.
• Fixture design: wiring, transformers and wattage ratings in a fixture are built for one voltage.

The same applies to E14 (14 mm, the European small base) and E12. E14 is not a safe substitute for E12, even though the two sizes look nearly identical. Always buy bulbs that match both the base and the voltage printed on the fixture or its manual. Each of our product pages lists the bulb base.

Other bulb bases you may run into

• E17: an intermediate base, 17 mm, sometimes found in appliances and small fixtures.
• E39: the mogul base, used in large industrial and outdoor fixtures.
• G9: a two-pin base used for small halogen or LED capsule bulbs.
• GU10: a twist-lock base common in spotlights.
• Integrated LED: no replaceable bulb at all. The LED is part of the fixture, and the whole light is replaced at end of life.

Many modern designs, including numerous LED wall sconces, use integrated LEDs. That means there is no bulb base to worry about, but you cannot change the bulb for a different color or brightness later.

How to find out which base your fixture uses

1. Switch the light off and let the bulb cool completely.
2. Check the label inside the socket or on the fixture, which usually shows the maximum wattage and base type.
3. Look at the product page or manual for a listing of the bulb base.
4. If you still are not sure, unscrew the bulb and read the code printed on the base or the packaging.
5. If the bulb has no markings, measure the threaded diameter with calipers: 26 mm is E26 and 12 mm is E12.

Wattage, lumens and dimming

The fixture's label sets the maximum wattage, and you should never go above it. With LED bulbs, you can use any bulb whose actual wattage is at or below that number, even if its box says it is "equal" to a much bigger incandescent. Look at lumens for brightness: an 800-lumen bulb is roughly equivalent to the old 60 W incandescent. For more on this, see our guide to color temperature, lumens and watts.

If the fixture is on a dimmer, choose bulbs marked dimmable and check the dimmer's compatibility. Enclosed glass shades can trap heat, so use bulbs that are rated for enclosed fixtures.

Which base should you choose for a new fixture?

Choose the base that suits how you want to use the light. E26 is the practical choice if you want easy bulb replacement and a wide range of brightness, for example in a pendant light over a dining table. E12 suits decorative fixtures where multiple small bulbs create sparkle, such as chandeliers and smaller wall sconces. If you prefer never to think about bulbs, an integrated LED fixture is the lowest-maintenance route.

Replacing a bulb is a simple job, but swapping a fixture is not. Switch off the breaker before working with a hardwired fixture and use a licensed electrician if you are unsure. Our guide to replacing a light fixture explains the process.

Frequently asked questions

Is E26 the same as a standard bulb?

In the United States, yes. A standard household screw-in bulb has an E26 base, also called a medium base.

Can I use an E26 bulb in an E12 socket?

No. The base is more than twice as wide and will not fit. Use an E12 bulb, or an adapter only if the fixture's shade and wattage limit allow it.

Can I use an E27 bulb in a US fixture?

It is not recommended. E27 bulbs are made for 230 V power and the thread differs slightly from E26. Use a bulb that is made for 120 V and marked with an E26 base.

What is a candelabra bulb?

A candelabra bulb is a bulb with an E12 base, often shaped like a candle flame, used in chandeliers and small decorative fixtures.