What Is An E26 Bulb?

Between Wattage, color temperature, brightness, light source, and so on, there is a lot of information to consider when you’re buying a light bulb.

If you’re not used to shopping for bulbs, you might be confused by all the different codes and specifications.

One you’ll see frequently is E26. It’s one of the most popular light bulbs in the US, but what does it mean?

E26 refers to the bulb’s base – how it is connected to the light fitting. It’s an Edison base, also known as a screw-type bulb, measuring 26mm in diameter. It’s suitable for any screw fitting that measures the same diameter.

In this article I’ll explain:

• What E26 means in more detail
• The differences (and similarities) between E26 and E27 bulbs
• The difference between A19 and E26 bulbs

What Does E26 Mean?

E26 refers to the base of your light bulb.

The base is the section at the bottom used to connect your bulb to the light fixture – it’s what keeps the bulb in place and what connects it to the circuit so that it can be powered.

There are different types of base that you can get, but that doesn’t mean you can choose which one to buy – it’s because there are different types of a fixture to suit different needs.

You need to buy the bulb that matches your fixture.

All base types are made up of either one or two letters and then a number which will either be one or two digits.

Base Type

The letter refers to the type of base.

In the case of an E26, that E stands for Edison, a base threaded to work in a screw fitting. It’s named after Thomas Edison, the creator of the original light bulb.

Other variants include bayonet bulbs (BA in North America, B in Europe) and pin-base bulbs (either G, GU, or GX, depending on the pin type).

Base Size

So that’s the letter – what about the number?

Well, the number is a measurement in millimeters that describes the width of the connector.

I say connector because it depends on the type of base as to what’s being measured.

With a screw-type Edison bulb, it’s the whole diameter of the base – so the bulb’s base is 26mm in diameter.

With other bulbs, particularly the pin-type bulbs, the measurement is not the width of the whole base but the distance between the pins.

Once you know this, it’s pretty easy to work out the base of your light bulb.

If your old bulb that needs replacing is a screw-type which measures 26mm in diameter at the base, you’ve got an E26.

E26 vs E27: What Is The Difference?

Once you know you’re looking for an E26 bulb and you start shopping online, you might see a lot of E27 bulbs for sale.

Now you know what E26 means, you’ll realize that E27 are almost identical, with just a one-millimeter difference. Except that they actually aren’t different in size after all.

Both E26 and E27 bulbs are actually made to the same agreed specifications that were set out by the International Electrotechnical Commission (IEC).

This means the diameter will measure somewhere between 26.05mm and 26.45mm. The exact dimensions for E26 bulbs are set out under IEC 7004-21A-2, while for E27, it’s IEC 7004-21-9.

E26 bulbs are more common in North America, while in Europe, you’ll tend to find E27 bulbs.

If you walk into any hardware store in the US, you’ll only find E26. Still, with stores online like Amazon selling bulbs from all over the world, you may see both available.

So, are they essentially the same bulb, just sold in different territories? The fitting and the dimensions are the same, right?

Well, technically, they aren’t exactly the same size – E27 bulbs tend to be slightly longer by a couple of millimeters.

Mechanically, though, they are interchangeable. So you’ll have no trouble screwing an E26 bulb into an E27 light fitting and vice versa.

But they are not the same bulb.

Just because they mechanically/physically fit into each other’s fittings, you need to be careful.

That’s because E26 bulbs are designed to be used on a 120V circuit, while E27 bulbs are designed for European 240V electrical systems.

Put an E27 bulb into an E26 fitting, and you’ll likely be fine – the bulb may not work effectively, but it won’t be dangerous.

But put an E26 bulb into a circuit with a higher voltage than it’s designed for, and you’ve got more risk of a short circuit or an electrical fire.

Related: Do I Need 2700K Or 3000K Bulb?

What Is The Difference Between A19 And E26 Light Bulbs?

When I mentioned the different types of base earlier, and the letters used to represent them (E, BA/B, G/GU), I didn’t mention A. You might’ve seen some A19 bulbs for sale that look remarkably like a screw base.

Well, A19 is actually the description of the bulb type and size – not the base.

It’s a little confusing because they’re so similar in style, but there are no bases that use the letter “A” – it’s all about the main body of the bulb, the glass, or the resin case for the light source.

A means “arbitrary,” but it’s essentially the ‘standard’ shape of a bulb with a rounded top.

The number 19 refers to how many eighths of an inch wide the bulb is at its widest point – so an A19 bulb is 19/8 inches (or 2 and 3/8 inches) wide.

That’s right – bulb bases are measured in metric millimeters. In contrast, bulb casings are measured in American (or what the Brits call “imperial”) inches.

Almost all A19 bulbs in the US have an E26 base, although the same is not true in reverse – there are a few different bulb shapes/sizes that also have an E26 base.

Also read: What Are Diffused LED Bulbs?

Final Words

Light bulb terminology can be a little confusing, especially when you have similar structures but mean different things (A19 vs. E26), and they even follow different measurement systems.

You’ll likely see E26 a lot when you’re shopping in stores or online because it’s one of the most popular standard fittings – and now you know what it means.

If you have a bulb that’s burned out, you should have no trouble identifying whether it’s an E26 or another bulb for you to replace.

Have you ever found yourself confused by all the different light bulb terms?

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