Most license plate lights use a small 12-volt bulb, commonly in a wedge-base (such as 194 or 168) or a festoon format, with LEDs increasingly used as replacements. The exact bulb depends on your vehicle, so verify the base and size by checking the owner's manual or inspecting the current bulb.
Common bulb types for license plate lights
Below are the formats you are most likely to encounter. Each type has its own socket and replacement considerations.
Wedge-base bulbs
Wedge-base bulbs push into a flat socket and are a frequent choice for license plate lighting. They are available in 12V incandescent forms and in LED drop-ins, and are typically labeled with numbers such as 194 or 168 (W5W is another catalog designation).
- 194 wedge bulbs
- 168 wedge bulbs
- W5W (a common wedge-base designation)
Concluding: If your housing uses a wedge socket, you’ll likely be choosing one of these sizes and bases. Always match the base and voltage to the socket.
Festoon bulbs
Festoon bulbs are glass tubes with contacts at both ends and are longer than wedge bulbs. They are common in older vehicles or certain trims and can vary in length (often around 31–39 mm or similar). They require the appropriate festoon size to fit the housing.
- 5 mm or 6 mm diameter festoon variants
- Typical lengths in the 31–39 mm range
Concluding: If you see a long, tubular bulb with two contact points at each end, you’re dealing with a festoon style.
LED replacement bulbs
LED versions are available for both wedge and festoon formats. They offer longer life and brighter, whiter light, but some cars may need CANBUS-compatible versions or resistors to avoid warning indicators or flickering.
- LED wedge replacements for 194/168 (often sold as 194 LED or W5W LED)
- LED festoon replacements (for 31 mm or 39 mm variants)
- CANBUS-compatible LEDs to minimize warnings on modern vehicles
Concluding: LEDs are popular for longevity and brightness, but always verify compatibility with your vehicle’s electrical system and any warning-light behavior.
Specialty bases
A small number of models use less common bases, such as BA9S or other compact formats. While rare for license plates, these can appear in some imports or specialty vehicles.
- BA9S or similar compact bases (less common for license plates)
Concluding: If you’re unsure, remove the existing bulb and compare the base and dimensions to a reference guide or bring it to a parts store for assistance.
How to identify the correct bulb for your vehicle
To avoid buying the wrong bulb, confirm both the base type and the socket fit, and consider whether you want incandescent or LED.
- Consult the owner’s manual or a parts diagram to confirm the exact bulb type and socket (wedge, festoon, or specialty).
- Inspect the installed bulb in the lamp housing and compare its shape, base, and length to the options above.
- Measure the bulb length if you suspect a festoon style, and check for any markings on the bulb itself.
- Check whether your vehicle requires CANBUS-compatible LEDs to avoid warnings or flicker.
- Purchase a replacement that matches the base, voltage (12V common), and fitment; consider replacing in pairs for uniform brightness if you’re upgrading to LEDs.
Concluding: Careful verification of base, length, and voltage will prevent compatibility issues and ensure a proper fit and illumination.
Summary
License plate lighting bulbs most commonly come in wedge-base (194/168/ W5W) or festoon formats, with LEDs available as direct drop-ins. Verify the base and length by checking the manual or the existing bulb, and consider CANBUS-compatible LEDs if you choose an upgrade. By identifying the exact socket type and size, you’ll ensure a smooth replacement and compliant illumination for your license plate.