The markings printed on a lamp are often the fastest route to a correct replacement. They may be faint, abbreviated or split across several lines, but each detail can help identify the product.

Markings vary by manufacturer and technology, so there is no single universal layout. The categories below explain what to look for.

Manufacturer and product code

The brand name and model code can identify the exact product family. Search or quote the complete code, including spaces, hyphens and suffixes. A final letter may distinguish colour temperature, beam angle, voltage or package type.

If the lamp is old, photograph the code before cleaning it. Printed ink can rub away.

Wattage

Wattage appears with W, such as 9W or 50W. It describes rated power consumption, not brightness. When selecting a replacement, never exceed the fixture’s maximum permitted wattage.

For LED replacements, the package may also state an “equivalent” incandescent wattage. Treat this as an approximate brightness comparison and use the lumen value for a more direct comparison.

Voltage

Voltage appears with V, sometimes as a single value and sometimes as a range. Examples include 12V, 120V and 220–240V. Some products also state AC, DC or AC/DC operation.

Do not infer voltage from the base. The same base family can appear on products designed for different electrical systems.

Lumens

Light output is marked in lm. A higher lumen figure generally means more total visible light, although the fixture and beam distribution determine where that light goes.

Colour temperature

Colour temperature appears in K, such as 2700K, 3000K, 4000K or 5000K. Lower values look warmer; higher values look cooler or more daylight-like.

Some manufacturers incorporate CCT into a three-digit colour code. For example, a code may combine an approximate CRI group with colour temperature. Because systems vary, confirm the manufacturer’s coding guide before interpreting it.

Colour rendering

CRI may be stated as a number, such as 80, 90 or 95. Higher values generally indicate better colour fidelity under the test method, but CRI is not the same as colour temperature or brightness.

Beam angle

Reflector and spotlight lamps may show an angle in degrees or a beam designation. Narrow beams concentrate light; wider beams spread it. PAR and MR lamp names describe the physical family, not the beam angle by themselves.

Base and shape codes

Codes such as E26, GU10, G9 or G13 identify the base. Codes such as A19, PAR30, MR16 or T8 describe the lamp shape or diameter family. Both may be needed for identification.

Rated life

Rated life may be stated in hours. This is a statistical or defined performance rating under specified test conditions, not a guarantee that every lamp will operate for exactly that time. Heat, switching, voltage, controls and fixture conditions can affect actual service life.

Dimming and location symbols

Look for text or symbols indicating:

• Dimmable or non-dimmable
• Indoor, damp or wet-location suitability
• Enclosed-fixture suitability
• Operating orientation
• Safety or certification marks
• Disposal instructions

When the markings are unreadable

Photograph the full lamp, base, socket and fixture label. Record dimensions and explain the application. A lighting specialist may identify the lamp from its construction and context, but specialised equipment may require the machine or fixture manual.

Keep a record of successful replacements. For a business, a simple register containing the location, lamp code, installation date and approved substitute can prevent repeated identification work and reduce inconsistent purchasing.