E26 vs E39: what is the difference?
E26 and E39 are Edison screw-base designations. The number refers to the approximate base diameter in millimeters: E26 is the common medium screw base, while E39 is the larger mogul screw base commonly encountered in higher-output commercial and industrial lamps.
How to identify the correct base
Do not rely on lamp shape alone. Check the existing lamp marking, fixture documentation, or manufacturer SKU. If the base designation is not printed, measure carefully or compare against manufacturer documentation.
Ordering rule: base type must match the socket. Similar-looking lamps with different Edison bases are not interchangeable simply because wattage or light output is similar.
Replacement checklist
- Base type: E26 or E39
- Voltage
- Maximum fixture rating
- Lumen requirement
- Color temperature
- Physical dimensions
- Enclosed/open fixture and environmental ratings
TECHNICAL CONTENTPrepared for practical product selection
Bright Concepts Lighting organizes manufacturer specifications and supplier product data to help commercial buyers identify and compare lighting products. Always verify the manufacturer documentation and project requirements before installation or substitution.