A incandescent e26 bulb leaning against an LED light bulb on a blue tabletop.

For safety and convenience, both incandescent and LED light bulbs are manufactured with standardized bases. One thing that hasn’t been 100% standardized, however, is the terminology used when naming the base sizes.

As a result, many find this a source of unnecessary confusion when shopping for replacement bulbs. In this post, you’ll learn all about the naming conventions of one of the most popular household bulb sizes and much more!

Are E26 and Medium Base Bulbs the Same?

Medium base and E26 bulb are interchangeable terms for Edison screw (ES) light bulbs with the same base size. These bulbs are some of the most commonly used in domestic light fixtures, and whether incandescent or LED, have a 26-millimeter thread diameter.

What is an Edison Screw Bulb?

Edison screw bulbs are named after Thomas Edison, inventor of the carbon filament light bulb. These light bulbs have screw bases that fit precisely and securely into a light fixture and are commonplace worldwide.

Including the medium base or E26 bulb, North America has four main Edison screw base sizes. 

Each has a colloquial name referring directly to its size:

Standardized CodeAlternative Name
E12Candelabra Bulb
E26Medium Base
E39Mogul Base

The E in the naming convention stands for Edison, and the number to its base diameter in millimeters. 

me holding up an e12 candelabra LED bulb with my bathroom light vanity fixture in the background
As a quick example of a smaller E12 socket base (candelabra bulb), I pulled this out of my bathroom vanity light fixture. You can see it’s much smaller than a regular E26 (regular bulb) socket base.

Are There Any Other Names for E26 Bulbs?

You will often see medium base or E26 bulbs referred to as standard, Medium Edison screw, or MES for short. But, again, these terms are interchangeable, so if you’re shopping for an E26 bulb and you see any of these names, they should fit just fine. 

What Types of Bulbs Come with E26 Fittings?

As mentioned, E26 bulbs have a standardized fitting, meaning that no matter the bulbs’ shape, they should physically fit in the fixture. 

Closeup on a homeowner's arms who's swapping an incandescent E26 bulb for a LED light bulb in a hanging ceiling fixture

The same goes for different bulb types. There are several available with E26 bases, including:

Incandescent Bulbs

Incandescent bulbs work on a tried and tested philosophy and can trace their heritage back to the original carbon filament light bulb. With these bulbs, electricity is passed through a filament which heats up and glows brightly.


  • Widely available
  • Inexpensive
  • Good color rendering
a closeup of an edison or incandescent light bulb turned on with a black background
You can see the filaments wrapped around inside with the bulb turned on of this incandescent light bulb


  • Low energy efficiency
  • Short lifespan
  • Heat output

Fluorescent Bulbs

Fluorescent bulbs contain mercury and argon gas. When this gas is exposed to electricity, it creates UV light. This UV light is converted to visible light by the phosphor coating on the inside of the tube, causing an intense white glow. 

A CFL e26 bulb stacked on a pile of cash and coins, indicating the savings provided by using this energy-efficient light bulb
This is your typical CFL (compact fluorescent) bulb that we have all probably bought and used at one point.

The majority of E26-sized fluorescent bulbs are Compact Fluorescent Lights (CFLs).


  • Energy efficiency
  • Long lifespan
  • Widely available


  • Higher upfront cost
  • Warm-up time
  • Contain mercury

LED Bulbs

LED bulbs use a semiconductor that emits light when a voltage is applied. They are widely considered the most efficient lamps and require very little energy to produce an extraordinary amount of light—they have a huge lifespan, with bulbs lasting an estimated 35,000–50,000 hours each.


  • Energy efficiency
  • Long lifespan
  • Durability
  • Instant on


  • Expensive to buy
  • Limited dimming range
  • Potential for flicker

Halogen Bulbs

Halogen bulbs are sealed units that contain a small amount of a halogen gas like iodine or bromine. They are incandescent and use a filament to produce light, but the presence of the halogen gas improves the efficiency over traditional incandescent, but not over fluorescent or LED bulbs. 

a closeup of a halogen bulb with a blue background
A closeup of the tiny halogen bulbs we’re used to buying for our car headlamps, track lighting, or other small-format light fixtures.

In my own experience, halogen bulbs can be very bright but also incredibly hot to the touch.


  • Produce bright, white light
  • Relatively inexpensive
  • Good lifespan


  • Easily damaged
  • Produce high heat during use
  • Poor energy efficiency
me holding up a burned out halogen light bulb with the hanging kitchen lamp behind it
Me replacing my tiny burned-out halogen light bulb. Not only will it not work anymore, but you can see how the curly filament burns totally off in the inside, indicating end of life.

Factors to Consider When Choosing an E26 Bulb

When it comes to finding the best E26 bulbs, there are a few factors you need to bear in mind.

Light Output

Light output is the first factor to consider. Specifically, how much light output do you need? Light output is measured in lumens; the higher the number, the greater the output. 

If you’re looking to light a sprawling space, you’ll want a bulb with a higher lumen rating. On the other hand, if you’re lighting a smaller area or trying to create a more atmospheric feel in the room, a lower lumen rating is a good option. 

Color (Kelvin) Temperature

The second factor to consider is the color temperature of the bulb. The color temperature is a reference to the appearance of the light produced by the bulb, measured in Kelvin.

E26 bulbs with high color temperatures make a cooler, whiter light. Bulbs with lower color temperatures have a warmer, yellower hue.

a modern looking graphic diagram of orange colors to white and bluish on the range, indicating different Kelvin color temperatures in lighting
It’s easy to get confused at the store about which kind of color (Kelvin) temperature output the bulb you’re buying actually emits. The box/packaging isn’t always so clear.

When choosing an E26 bulb based on color temperature, consider the color scheme of the room, as well as the ambiance you’re trying to create.

Energy Efficiency

Third, think about energy efficiency. Since 2007 and the introduction of the Energy Independence and Security Act, the US has been phasing out inefficient light bulbs.

If you plan to run your lights for an extended period, LED or CFL is the best approach. They cost very little to run, and their lifespan is exceptional. However, if you only plan to turn on your lights periodically and you’re looking for a specific aesthetic, incandescent or halogen bulbs might work for your particular case.

There are some great monitors available for monitoring your home’s energy consumption. If you want to keep a better eye on which devices are your home’s most significant energy hogs, check out our roundup of the best devices for monitoring energy consumption.


Factor number four is lifespan. Be sure to consider the estimated lifespan of your medium base bulb before making your decision. LEDs last the longest by a considerable margin. Compact fluorescent bulbs tend to have the second most extended lifespan, followed by halogen, and finally incandescent.

The longer the bulb’s lifespan, the less often you’ll need to change it, which in the case of LED bulbs, can offset the initial purchase price. Additionally, if you have lights in awkward, inaccessible places (on a high ceiling, for example), choosing a long-life bulb will mean fewer trips up the ladder!


Next, be sure that the E26 bulbs you choose are compatible with the electrical in your home. You will need to be sure that the rated voltage on the bulb is correct, and if your light has a dimmer switch, check the bulbs for compatibility. 

Most incandescent E26 bulbs will work perfectly with a dimmer, but you might encounter flickering or a limited range of light output if you install incompatible CFL or LED bulbs.

Make sure the light bulb you choose is compatible with your fixtures and lamps. E26 bulbs have a standard base size, but checking that the bulb will fit and function properly in your specific fixtures is critical.

Check that any bulb you choose sits within the maximum wattage rating of your fixtures. Going outside of this range can cause serious safety issues, including fire.

Environmental Impact

Illustration of an incandescent bulb and a CFL light bulb side by side, with a checkmark next to the CFL, indicating an Energy-Efficient Light Bulb

The final factor to consider is any potential environmental impact. Energy-efficient light bulbs like LED produce the same or more light while using less energy than incandescent or halogen bulbs. If you want to reduce your carbon footprint, energy-efficient lighting is a great way to start.

Additionally, as discussed in our 17 Energy Efficiency-Improving High ROI Home Upgrades post, upgrading to energy-efficient bulbs is one of the most affordable ways to reduce electricity costs.

Moreover, some light bulbs, like halogen or CFL, can contain harmful materials such as mercury. This composition means they must be disposed of carefully to prevent direct environmental damage. If you don’t have proper disposal facilities, consider switching to an LED E26 bulb to replace your halogen or CFL light.

Final Thoughts

While both E26 and medium base are frequently used terms, they both refer to the same thing—an Edison screw bulb with a 26mm diameter base. 

In addition to medium base and E26 bulbs, you might also see them referred to as standard or Medium Edison Screw (MES). No matter which you see, remember that they are all physically interchangeable.

Leave a Reply

Your email address will not be published. Required fields are marked *