Audi A4 2021 Bulb Size
Bulb size chart
This page helps you verify the bulb sizes for the 2021 Audi A4 by lighting position, so you can match the correct bulb before ordering. Because Audi used different lighting setups depending on trim, package, and market, checking the exact location is the safest way to confirm fitment for exterior and interior lights.
For the 2021 Audi A4, many positions use LED lighting, while some headlight and front turn signal setups vary by equipment. Use the bulb chart on this page to compare the light position on your car with the listed bulb type, especially if your A4 has LED headlights, HID headlights, or a different trim-level lighting package.
Fitment can change with body style, region, and optional equipment, so always compare your car’s installed bulb and housing before buying replacements. The 2021 Audi A4 may use LED assemblies in many places, but some versions still differ between halogen, HID, and LED headlight configurations, and aftermarket conversions can affect compatibility. If you are replacing a bulb, inspect the original part number or remove the bulb first to confirm the exact match before purchase, especially for front turn signals, headlights, and any exterior lighting that may have been upgraded previously.
FAQ
Does the 2021 Audi A4 use the same bulb sizes on every trim?
Not always. Trim level, lighting package, body style, and market can change the bulb setup, especially for headlights, front turn signals, and cornering lights.
Which lighting positions on the 2021 Audi A4 are listed as LED?
Many positions are listed as LED, including the center high mount stop light, brake light, license plate light, parking light, tail light, daytime running light, rear turn signal, reverse light, and several interior lights.
What bulb is used for the glove box light on the 2021 Audi A4?
The glove box light bulb is listed as 2821.
What bulb is used for the front turn signal on A4 models with HID headlights?
The front turn signal bulb for versions with HID headlights is listed as 64132.
What headlight bulb type is used on the 2021 Audi A4 with HID headlights?
The HID headlight bulb type listed for high beam, low beam, and combined high/low beam applications is D5S.
What bulb is listed for the front turn signal on A4 models without the HID headlight setup?
The front turn signal bulb listed for that setup is 12174NA.
Does the 2021 Audi A4 use different headlight bulbs with LED headlights?
Yes. For A4 models with LED headlights, the headlight high beam and low beam positions are listed as LED rather than a replaceable halogen-style bulb.
Is the cornering light on the 2021 Audi A4 always LED?
The cornering light is listed as LED with an H8 LED note, so it should be checked against the exact lighting package on the vehicle.
Why should I check the installed bulb before ordering parts?
Because the 2021 Audi A4 can have different lighting configurations, and the same model year may use different bulbs depending on the equipment installed from the factory or changed later.
Can aftermarket LED conversions change fitment on the 2021 Audi A4?
Yes. Aftermarket conversions can alter bulb type, connector fit, heat management, and error-free operation, so it is important to verify the actual bulb and housing before buying replacements.
Are interior bulbs on the 2021 Audi A4 all the same?
No. Interior lighting positions such as vanity mirror, dome, map, interior door, trunk or cargo area, stepwell, and glove box can use different bulb types or LED modules depending on the vehicle.
What is the best way to use this page for bulb replacement?
Match the lighting position on your 2021 Audi A4 to the chart, confirm whether your car has LED, HID, or another headlight package, and then verify the installed bulb or part number before ordering.