There isn’t a single universal bulb size for license plate lights. In most modern cars, the lamp uses either a wedge-base bulb (commonly sold as W5W, and labeled 194 or 168) or a small festoon bulb (about 31 mm long). The exact size depends on your vehicle’s make, model, and year. Start by checking your owner’s manual, inspecting the current bulb, or searching by your car’s exact year, make, and model to confirm the correct size.
Common lamp configurations you’ll encounter
License plate lights are typically grouped into a few base types. Knowing which base your car uses helps you shop accurately and avoid returns.
- Wedge-base bulbs (commonly W5W) — often labeled 194 or 168 in shops. These slide into a wedge socket and are easy to replace from behind the license plate housing.
- Festoon bulbs — cylindrical bulbs held between two contacts, with length measured in millimeters (31 mm is typical for many cars; some models use 42 mm or other lengths).
- Bayonet bases — less common on newer vehicles, but found on some European models; bases include BA9s or BA15s with a push-and-twist fit.
Knowing the base type (wedge, festoon, or bayonet) is the key to selecting the right replacement, and it’s always wise to confirm with your specific vehicle’s documentation or an in-person bulb check.
How to confirm the exact size for your car
If you want to identify the precise bulb quickly, follow these steps.
- Locate the license plate light housing above or beside the plate on your vehicle.
- Access the bulb by removing the lens or module from the housing (usually requires a small screwdriver or release tab).
- Note the base type (wedge, festoon, or bayonet) and the approximate length or fitment mark on the bulb itself.
- Match the base type and size to the vehicle’s manual or parts lookup for your exact year, make, and model. If you’re unsure, remove the old bulb and take it to an auto parts store for a precise match.
- Decide whether you want the same size replacement or an upgrade (for example, LED) and ensure compatibility (CANbus, brightness, fitment) for your vehicle.
These steps help prevent ordering the wrong bulb and minimize the hassle of returns or exchanges.
Typical sizes you’ll see in the market
While sizes vary, these are the most frequently encountered options for license plate lighting across a wide range of vehicles.
- Wedge-base: W5W, commonly sold as 194 or 168 bulbs.
- Festoon: 31 mm length is the standard for many cars; some models use 42 mm or other lengths.
- Bayonet bases: BA9s or BA15s on certain European or older models.
Because car design differs by year and market, always verify the exact bulb size for your specific vehicle before purchasing replacements.
LED replacement considerations
LED upgrades for license plate lights can offer longer life and brighter illumination, but they come with compatibility caveats.
- CANbus compatibility — some cars monitor exterior bulbs and may trigger warning lights or hyper-flash if the load changes significantly. Look for “CANbus-ready” or include a resistor.
- Fit and polarity — LED replacements must align with the existing base type; some LEDs require correct orientation or a capacitor/resistor to function properly.
- Brightness and color — license plate illumination is typically white; choose a color temperature that complies with local regulations and avoids excessive glare.
- Installation considerations — LED modules may be longer than the original bulb and could require extra space or a different housing method.
Key considerations for LED replacements
When weighing LED options, prioritize vehicle compatibility, regulatory compliance, and the ease of installation. Always verify that the LED bulb you buy matches the exact bulb size and base type of your license plate light, and consider a CANbus-capable option if your vehicle’s electrical system expects a traditional bulb load.
Summary
The bottom line is simple: there is no single universal license plate bulb size. Most cars use either a wedge-base bulb (W5W, often labeled 194 or 168) or a 31 mm festoon bulb, with some models using bayonet bases. To be sure, check your owner’s manual, inspect the current bulb, or search by your vehicle’s exact year, make, and model. If you’re upgrading to LEDs, verify CANbus compatibility and fitment to avoid electrical or regulatory issues, and consider color temperature and regulatory requirements in your area. With the right size confirmed, replacement is typically a quick and straightforward task.)