Factory setup not specified in fitment source

2018 Audi A4 Headlight Bulbs & Lighting Guide

Choose the factory headlight system below to see the correct bulb and recommendation path for this 2018 Audi A4.

Low beam
Factory halogen system
High beam
H11
Factory setup
Factory setup not specified in fitment source

Choose the factory system installed in this vehicle. Bulb sizes and recommendations change with that selection.

2018 Audi A4 representative vehicle image

Best headlight upgrades

These products were physically tested by BulbFacts, but the tests were not performed in this exact vehicle unless a card explicitly says otherwise.

Factory setup not specified in fitment source

High Beam: H11

Best direct replacement

OSRAM Night Breaker 200

High Beam H11

BulbFacts testedCorrect bulb size
Best Standard Reflector Upgrade

The Night Breaker 200 is the top standard-wattage reflector recommendation at the time of review. Anything scoring higher in the reflector chart uses much higher wattage, while the NB200 keeps the simple drop-in halogen format.

General BulbFacts housing test
Read BulbFacts reviewCompare test resultsBuy at eBay

A matching bulb size identifies fitment; it does not by itself prove optical compatibility or make a conversion a vehicle-specific recommendation.

Support independent testing: BulbFacts may earn a commission from qualifying purchases through these links, at no extra cost to you. Affiliate relationships do not determine test results or recommendations.

Other bulbs

Available exterior and interior lighting data for this model year.

Brake Light
1156Possible fitment — verify installed bulb
Cornering Light
H11Possible fitment — verify installed bulb
Fog Light
T15Possible fitment — verify installed bulb
Tail Light
T15Possible fitment — verify installed bulb
Turn Signal (Unqualified)
BAU15SPossible fitment — verify installed bulb
Front Turn Signal
PW24WLikely fitment
Brake Light
T15Likely fitment
Technical details and sources

Fitment, factory-system research, and BulbFacts product tests remain separate evidence. A matching bulb size does not by itself make a conversion a vehicle-specific recommendation.

PositionBulb or systemEvidence status
High BeamFactory setup not specified in fitment sourceH11Possible fitment — verify installed bulb
High/Low Beam CombinedLighting: HIDD5SLikely fitment
High/Low Beam CombinedModel: allroad; Lighting: HIDD5SLikely fitment
High BeamModel: allroadH11Likely fitment
High BeamModel: QuattroH11Likely fitment
High/Low Beam CombinedModel: QuattroD5SLikely fitment

Each model year opens its own BulbFacts record. Bulb sizes and factory systems are not carried over from adjacent years.

Fitment note: Verify the installed bulb, connector, housing, and factory system before ordering. A bulb-size match is not automatically a conversion recommendation or proof of vehicle-specific testing.