Most license-plate lights use a small 12-volt automotive bulb in a festoon or wedge base, or an LED module designed to fit the same socket. The exact size and shape vary by vehicle, so check your owner's manual or inspect the current bulb to identify the correct replacement.
Identify the exact bulb for your vehicle
Use these steps to determine the right bulb size, base type, and replacement options. Getting it right the first time saves trips to the parts store and avoids fit issues.
- Consult your vehicle's owner’s manual or a service manual for the exact bulb specification.
- Inspect the existing bulb and socket to determine base type (festoon vs wedge) and approximate length.
- Look for a part number on the bulb or in the lens area, if visible.
- Use an online bulb finder or the parts store’s database by entering your car’s year, make, and model.
- Bring the old bulb to a store or compare photos online to confirm compatibility.
Having confirmed the socket type and size, you can shop with confidence or order a direct replacement from the manufacturer.
Common shapes you might encounter
License-plate lighting uses a few standard bulb families. The exact option for your car depends on its design and year.
Festoon style (cylindrical)
Festoon bulbs are common in European and many modern vehicles. They sit inside a small lamp holder with contacts at each end and come in lengths such as 31, 37, or 39 millimeters. Some variants use a double-ended base for plug-in LED options.
- Typical lengths include 31–39 mm, with a simple plug-in contact at each end
- Common in many European models and some modern U.S. cars
Check your car’s lens and socket to confirm the length and whether a plug-in LED festoon is compatible.
Wedge/base bulbs and LED replacements
Many cars use wedge-base bulbs that push into a two-prong socket (common types are T10/W5W). LED replacements are popular for longer life and brighter light, often sold as 194/168 equivalents in the U.S. market. When using LED units, ensure polarity if required by the socket, and buy high-quality white LEDs (roughly 5000–6500K) to match license-plate lighting standards.
- Common wedge bases include T10 and W5W
- LED replacements are widely available and may include CAN-bus-compatible options to avoid dashboard errors
LED modules or complete assemblies can be used when the housing supports them, sometimes with resistors or drivers built in to prevent flicker or code errors.
How to replace safely
Replacing a license-plate bulb is usually straightforward, but following simple safety steps helps prevent damage or shorts.
- Turn off the vehicle and remove the key; ensure the interior lights are off
- Access the license-plate light housing by removing the plate or the lens cover
- Disconnect the wiring connector if present and remove the old bulb
- Insert the new bulb, ensuring the correct orientation for wedge bases or aligning end caps for festoon
- Reconnect wiring, reattach the lens or plate, and test the light in darkness
With the bulb replaced, reattach the plate and verify illumination ensuring even brightness and no flicker.
Regional considerations and legality
In many jurisdictions, license-plate illumination must use white light and meet brightness standards. Colored bulbs (red, blue, amber) are often illegal behind a plate. If you replace with LED, confirm color and brightness comply with local rules and watch for any dashboard error codes on modern vehicles.
Tips and quick references
Getting it right means choosing the right fit and color. Here are quick pointers to help you shop.
Quick regional guide
United States: common small bulbs include wedge-base 194/168 types in many cars; some older models use festoon-style bulbs around 31–39 mm. Europe and other regions often use festoon 31–39 mm or wedge equivalents (T10/W5W). LED replacements are widely available for both styles.
- Always verify by identifying the current bulb or checking the owner’s manual
- Choose white light (approximately 5000–6500K) for license-plate illumination
- Consider CAN-bus-compatible LEDs to avoid triggering error codes on modern vehicles
Tip: bring the old bulb or a photo of the socket to the parts store or use an online fitment tool with your car’s make and model.
Summary
License-plate bulbs come mainly in festoon (cylindrical) or wedge-base forms, with LED upgrades readily available. To get the right bulb, identify the socket type from your manual or the existing bulb, confirm length and base, and ensure the color and brightness meet local regulations. When in doubt, consult a parts specialist and bring the old bulb or a photo of the socket. Consistent, legal illumination helps keep plates clearly readable at night and compliant with local laws.