E26 and E27 bases are almost the same size and differ in the voltage they were made for: E26 for 120 V lamps in North America, E27 for 220 to 240 V lamps in continental Europe and China (Wikipedia). Match the bulb to the holder and the supply. For a glass shade, send your holder drawing and we drill the opening to fit it (SIGA, 2026).
- In E26 and E27, the number is the base diameter in millimeters and E stands for Edison (Wikipedia, 2026).
- The two bases fit each other physically, but an E26 bulb in an E27 holder at 240 V may be an electrical hazard (Waveform Lighting, 2026).
- An E27 bulb can generally go in an E26 holder if its voltage rating suits the supply (SuperBrightLEDs, 2026).
- For a glass shade, the holder collar size sets the opening. The base name does not (SIGA, 2026).
Edison screw is a screw-thread bulb base. The number after the E gives the thread diameter in millimeters, measured across the thread peaks (Wikipedia).
Lamp holder is the socket that receives the bulb base. It is also called a bulb holder or socket.
IEC 60061-1 is the international standard for lamp caps, published with gauges for checking interchangeability and safety (IEC Webstore).
The base names are easy to confuse, because E26 and E27 sound different and are almost the same size. If the holder is misread, the opening may not fit the collar. This guide explains what each base is, which markets use it, what is safe to mix and what to send us.
What do E26 and E27 mean?
E26 and E27 are Edison screw bases, 26 mm and 27 mm across (Wikipedia). E26 is the medium screw for lamps on a North American supply, and E27 serves lamps on the continental European and Chinese supply. The smaller E12 and E14 suit candelabra and small fittings.
Voltage is the real divider. Incandescent bulbs were made for one voltage: E26 for about 120 V and E27 for about 240 V (Waveform Lighting). Some LED bulbs run at any voltage from 90 V to 240 V, so the LED label matters more than the base name.
| Base | Diameter | Typical use |
|---|---|---|
| E12 | 12 mm | Candelabra fixtures and night lamps |
| E14 | 14 mm | Chandeliers, night lamps, some pendant lights |
| E26 | 26 mm | 120 V lamps in North America |
| E27 | 27 mm | 220 to 240 V lamps in continental Europe and China |
| E39 | 39 mm | High-power 120 V lamps |
How different are E26 and E27 in size?
They are almost the same. A lighting retailer's guide gives both bases one diameter range, 26.05 to 26.45 mm, and says E27 has a longer minimum screw length and a taller insulator, which suit the higher voltage (Waveform Lighting).
Treat those dimensions as secondary. They come from a retailer, and the defining documents are the standards: IEC 60061-1 for lamp caps (IEC Webstore) and the matching ANSI C81 series in North America (Wikipedia). We could not read the paid standards, so check any dimension you design around against them or ask a qualified electrician.
How do I find out which base my holder takes?
Read the base code on the bulb package or on the bulb itself, and compare it with the holder. If there is no marking, measure across the thread peaks, because the number in the name is that diameter in millimeters (Wikipedia). A reading near 14 mm means E14, but a reading near 26 or 27 mm cannot separate E26 from E27, since the two share one diameter range; for those, go by the marking on the bulb or the holder and the supply voltage.
Photograph the holder from the side with a ruler beside it. That photo, plus the market and voltage, answers most of the questions we would ask.
Can I use an E26 bulb in an E27 holder?
Avoid it at 240 V. An E26 bulb fits an E27 holder physically, but it may be an electrical safety hazard at that voltage (Waveform Lighting). The reverse is generally considered safe when the E27 bulb is rated for the holder's voltage (SuperBrightLEDs).
The practical rule is to buy the bulb for your market. A lamp sold in North America takes an E26 holder, and one sold in Europe takes E27. If you sell in both, plan two holder variants and tell us which one each batch uses.
Which base suits small glass shades?
Smaller shades often sit on smaller bases. Wikipedia lists E14 for chandeliers, night lamps and some pendant lights, and E12 for candelabra fixtures (Wikipedia). A small shade on an E14 or E12 holder needs a smaller opening than one on an E26 or E27 holder. So the holder you choose sets the opening, and the opening sets how much of the glass can be a plain neck.
What does the glass shade factory need to know?
Send the holder drawing or a photo, the opening size and any extra holes (SIGA, 2026). The opening is drilled with a drill bit of the matching size, so the number we drill to is a measurement from your holder, not a base name. Our fitting guide lists what to send, and the drawing must state the opening's inner diameter and position (SIGA, 2026). Our size chart shows how to measure. Our glass pendant light shades page shows pendant shapes with an opening for a holder like these.
This is our judgment, not a standard. Two E26 holders from different makers can have different outer collars, and a pendant canopy can add a ring that the glass must clear. Send the holder as it will sit in the lamp.
UK buyers often ask about bayonet bases such as B22, because the UK and much of the Commonwealth use bayonet fittings instead of Edison screws (Wikipedia). We do not deal with the bulb base or the holder type. We drill the opening to your drawing, so send the holder drawing whatever the base (SIGA, 2026).
What can go wrong, and what do we not check?
The way to avoid a mismatch between collar and opening is to send the holder and not only the base name. We have not met such a mismatch so far. We cannot check your electrical design or certification, and we are not the right supplier for that part of the job. Tell us the market, the voltage and the holder in the first message, and have your lamp maker confirm the electrical details (SIGA, 2026).
| Item | What to send |
|---|---|
| Market and voltage | For example 120 V, or 220 to 240 V |
| Base | E12, E14, E26, E27 or other |
| Holder | Drawing or photo with the collar size |
| Opening | Diameter you need in the glass |
| Extra holes | Position and size |
Sources and Further Reading
- IEC Webstore: IEC 60061-1, Lamp caps. The title page of the international standard that defines lamp caps. The standard itself is paid. Checked 2026-10-17.
- Waveform Lighting: E26 vs E27 bulbs. A retailer's guide to the two bases, their voltage ratings and interchangeability. Secondary source. Checked 2026-10-17.
- SuperBrightLEDs: light bulb base types. A retailer's guide to E12, E14, E26 and E27 and where each is used. Secondary source. Checked 2026-10-17.
- Wikipedia: Edison screw. A general background article on base sizes and the ANSI and IEC standards. Checked 2026-10-17.
Frequently Asked Questions
Is E26 the same as E27?
No, though they are nearly the same size. E26 is the 120 V standard in North America and E27 is the 220 to 240 V standard in continental Europe and China (Wikipedia, 2026). The two fit each other physically, but you should match the bulb's voltage rating to your supply and your holder (Waveform Lighting, 2026).
Which bulb base should I specify for a pendant shade?
Specify the base your lamp holder uses, and send the holder drawing or a photo with its collar size. We drill the opening to fit the holder, so the collar measurement matters more than the base name when the glass is made.
Can one glass shade fit both E26 and E27 holders?
Possibly, if both holders have the same collar size. That is our judgment and not a standard: collars differ between makers. Send both holder drawings with your order so the collar sizes can be compared.
Can you make shades for UK bayonet holders?
As far as the glass goes, yes. We do not deal with the bulb base or the holder type; we drill the opening to your drawing. Send the drawing of your B22 or other holder with the collar size, and have your lamp maker confirm the electrical side (SIGA, 2026).
Send your holder drawing, voltage and opening size with your shade drawing, and we reply within 12 hours.
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