Light Bulb Bases
Indoor Climate & Fixtures · 9 specs
Direct Answer
Domestic light bulb bases standardize screw (Edison) and pin configurations. The E26 (26 mm) base serves as the standard medium screw in 120V North America, E27 (27 mm) in 230V Europe, E12 (12 mm) for candelabras, and GU10 for 120V/230V twist-lock track spotlights.
Source: IEC 60061 (Lamp Caps and Holders) / ANSI C81.61 · Last reviewed Aug 28, 2026
Specs
| Governing Standards | IEC 60061 / ANSI C81.61 (Electric Lamp Bases) |
| E26 Medium Edison Screw | 26 mm (1.02") diameter | Standard North American residential lamp base (120V) |
| E27 Medium Edison Screw | 27 mm (1.06") diameter | Standard European/International residential base (230V) |
| E12 Candelabra Screw | 12 mm (0.47") diameter | US chandeliers, nightlights, sconces, holiday bulbs |
| E14 Small Edison Screw (SES) | 14 mm (0.55") diameter | European candelabra and small accent fixture standard |
| E39 / E40 Mogul Screw | 39 mm (US) / 40 mm (EU) | High-wattage commercial & industrial fixtures |
| GU10 Bi-Pin Twist-Lock | 10 mm pin spacing with mushroom feet | 120V/230V mains voltage spotlights |
| G9 Looped Bi-Pin | 9 mm looped pin spacing | 120V/230V compact halogen/LED capsules |
| MR16 (GU5.3) | 5.3 mm pin spacing | 12V low-voltage directional spotlight base |
Domestic Light Bulb Base Classification Matrix
| Base Designation | Base Type | Major Diameter / Pin Spacing | Nominal Voltage | Common Fixture Applications |
|---|---|---|---|---|
| E26 | Medium Edison Screw | 26 mm (1.02") | 120V (North America) | Universal household lamps, ceiling fixtures, outdoor lanterns |
| E27 | Medium Edison Screw | 27 mm (1.06") | 230V (Europe/UK/Global) | Universal international household socket standard |
| E12 | Candelabra Screw | 12 mm (0.47") | 120V (North America) | Chandeliers, wall sconces, ceiling fan light kits, nightlights |
| E14 | Small Edison Screw (SES) | 14 mm (0.55") | 230V (Europe/Global) | European chandeliers, desk lamps, appliance bulbs |
| E39 / E40 | Mogul Edison Screw | 39 mm / 40 mm (1.54") | 120Vā277V Commercial | High-bay warehouse lighting, streetlamps, commercial floodlights |
| GU10 | Twist-Lock Bi-Pin | 10 mm pin spacing | 120V / 230V Mains | Track lighting, recessed ceiling directional spotlights |
| GU5.3 (MR16) | Straight Push-Pin | 5.3 mm pin spacing | 12V Low Voltage | Low-voltage landscape lighting, museum recessed spotlights |
| G9 | Looped Wire Bi-Pin | 9 mm loop spacing | 120V / 230V Mains | Modern designer chandeliers, vanity sconces, compact fixtures |