E10, E12 and E14 bulbs – what’s the difference?

When you shop for bulbs online and compare a product image on the computer screen to the old bulb you have in your hand, it’s hard to tell if the screw or bayonet cap is the right size. This is especially challenging with small screw caps where there are only a few millimeters of difference between sizes.

But don’t worry. Once you understand what the cap types mean, and with the help of your trusty tape measure or ruler, you can be confident that you’ll order the right bulb every time.

E14 lamp holderBrowsing the online shop, you’ll need to look in the product description or specification for the code used to describe the bulb's cap. For screw-in fittings, the code will start with the letter ‘E,’ which stands for Edison Screw. The second part of the code is a number that corresponds to the diameter of the lamp holder the bulb’s screw fits into. For example, an E10 screw fits into a 10mm diameter holder, an E14 screw fits into a 14mm diameter holder, and so on.

Notice I mentioned the diameter of the lamp holder rather than the bulb’s screw? That’s because the actual screw cap on the bulb is slightly smaller in diameter than the fitting. If they were exactly the same size, the screw wouldn’t fit! The exact measurements of the screw caps are:

 

Screw Cap Name

Diameter in Millimeters

E10

9.3mm

E12

11.5mm

E14

13.5mm

E27

26mm

E10, E12, E14 screw bases

All of our product pages show the cap fitting in the product specification.

E10

Also referred to as MES (Miniature Edison Screw), these are commonly found in old chandeliers, so bulbs designed to fit E10 lamp holders tend to be more decorative in appearance to suit the light fitting. You will also find bulbs with E10 caps in miniature lamp applications and indicating panels.

E10 candle bulbs > | E10 Panel bulbs >

E12

This size is more commonly found in America and is used in old or imported candelabra fittings. It is the least common of the screw sizes, so it is unlikely to be stocked in your local supermarket. Luckily, you can still find a good range online from specialist bulb suppliers (just like us!).

E12 candle bulbs >

E14

Also known as SES (Small Edison Screw), this is a very common size used throughout Europe and the UK. It is found in many types of small light fittings around the home, from bedside table lamps to wall lights and chandeliers. Many shapes of bulb are available with an E14 cap, including candles, golf balls, small reflector spotlights, and small decorative filament bulbs. Be sure to choose the shape that best suits your fitting.

E14 candle bulbs > | E14 golf ball bulbs >

E27

Known as ES (Edison Screw), this is the standard screw size used in most large mains voltage light fittings. It’s uncommon for this size to be used in delicate chandeliers or old fittings, but there are always exceptions. A wide range of shapes is available for bulbs with an E27 cap.

E27 candle bulbs > | E27 golf ball bulbs > | E27 GLS bulbs > | E27 globe bulbs >