The difference between an E26 and an E27 bulb base

The diameters of the E26 and E27 bulb bases differ by 1mm. From an electrical usage point of view, they are different. You need to choose E26 or E27 bulbs depending on the voltage in your area to avoid unnecessary electrical risks.

Before buying a bulb or after moving house, this article can help you understand bulb base choose.

Edison screw base types

The “E” here is an acronym for Thomas Alva Edison, the inventor of the screw lamp holder. The number after “E” refers to the current maximum diameter of the screw base. There are E10/E11/E12/E14/E17/E26/E27/E39/E40 respectively.

CandelabraIntermediateMedium (Standard)Mogul
North AmericaE12E17E26E39

E26 VS. E27

The difference between the bases is the mechanical difference, and the required standard voltage.

E26 as North American standard base, using 120V AC
E27 as a European standard base, using 240V AC


Length of screw (min)
19.56 mm22.0 mm

Live contact pad width
9.14 mm – 11.56 mm4.8 mm – 11.5 mm

Insulator height (min)
3.25 mm5 mm

Screw diameter at thread peak
26.05 mm – 26.41 mm26.05 mm – 26.45 mm

Screw diameter at thread trough (max)
24.72 mm24.26 mm

Distance between threads (OC)
3.629 mm3.629 mm

Does your region use E26 or E27?

The required standard bulb bases can be found based on the standard voltage ratings in the current region.

Continent or RegionE26E27
AsiaJapan, Taiwan.Afghanistan, Armenia, Bahrain, Bangladesh, Bhutan, British Indian Ocean Territory, Brunei, Burma, Cambodia, China, Christmas Island, Cocos (Keeling) Islands, Hong Kong, India, Indonesia, Islamic Republic Of Iran, Iraq, Israel, Jordan, Kazakhstan, Korea, Kuwait, Kyrgyzstan, Lao People’s Democratic Republic, Lebanon, Macao, Malaysia, Maldives, Mongolia, Myanmar, Nepal, Oman, Pakistan, Palestinian Territory, Philippines, Qatar, Saudi Arabia, Singapore, South Korea, Sri Lanka, Syria, Tajikistan, Thailand, Timor Leste, Turkmenistan, United Arab Emirates, Uzbekistan, Vietnam, Yemen.
AfricaLibya.Algeria, Angola, Benin, Botswana, Burkina Faso, Burundi, Cameroon, Cape Verde, Central African Republic, Chad, Comoros, Congo, The Democratic Republic Of The Congo, Ivory Coast, Djibouti, Egypt, Equatorial Guinea, Eritrea, Ethiopia, Gabon, Gambia, Ghana, Greece, Guinea, Guinea Bissau, Kenya, Lesotho, Liberia, Madagascar, Malawi, Mali, Mauritania, Mauritius, Morocco, Mozambique, Namibia, Niger, Nigeria,Reunion, Rwanda, Saint Helena, Sao Tome And Principe, Senegal, Seychelles, Sierra Leone, Somalia, South Africa, Sudan, Swaziland, (United Republic Of) Tanzania, Togo, Tunisia, Uganda, Western Sahara, Zambia, Zimbabwe.
North AmericaAnguilla, Bahamas, Barbados, Belize, Bermuda, Canada, Cayman Islands, Costa Rica, Cuba, Dominican Republic, El Salvador, Guatemala, Haiti, Honduras, Jamaica, Mexico, Nicaragua, Panama, United States, British Virgin Islands.Antigua and Barbuda, Dominica, Greenland, Grenada, Guadeloupe, Martinique, Montserrat, Saint Barthélemy, Saint Kitts And Nevis, Saint Lucia, Saint Martin, Saint Pierre And Miquelon, St. Vincent, Turks And Caicos Islands.
South AmericaAruba, Colombia, Ecuador, Trinidad and Tobago, Venezuela.Argentina, Bolivia, Brazil, Chile, Falkland Islands (Malvinas), French Guiana, Guyana, Paraguay, Peru, Suriname, Uruguay.
AntarcticaBouvet Island.
EuropeAland Islands, Albania, Andorra, Austria, Azerbaijan, Belarus, Belgium, Bosnia And Herzegovina, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Faroe Islands, Finland, France, Georgia, Germany, Gibraltar, Guernsey, Holy See (Vatican City State), Hungary, Iceland, Ireland, Isle Of Man, Italy, Jersey, Kosovo, Latvia, Liechtenstein, Lithuania, Luxembourg, Macedonia, Malta, Republic of Moldova, Monaco, Montenegro, Netherlands, Norway, Poland, Portugal, Romania, Russia, San Marino, Serbia, Slovakia, Slovenia, Spain, Svalbard And Jan Mayen, Sweden, Switzerland, Turkey, Ukraine, United Kingdom.
OceaniaAustralia, Cook Islands, Fiji, French Polynesia, Kiribati, Nauru, New Caledonia, New Zealand, Niue, Norfolk Island, Papua New Guinea, Pitcairn, Samoa, Solomon Islands, Tokelau, Tonga, Tuvalu, Vanuatu.


Is it interchangeable?
There is a 1mm gap between the two and they are interchangeable from a mechanical point of view. From an electrical safety standpoint, no.

What is the best compatibility?
The base of the bulb and the socket of the bulb are matched to each other, and the rated voltage is also matched.

Can E27 bulbs be used in the US?
Yes, but not recommended. Because the required voltage is different, the brightness of the bulb will drop by half in this case.

Can E26 bulbs be used in Europe?
No, because the standard rated voltage required by E26 is 120V AV, the bulb will burn out instantly when used in a 240V AV environment.

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