What Is a 9006 Bulb? | The Halogen Headlight Standard

A 9006 bulb is a 12V, 55W halogen headlight bulb with a P22d base, used mainly for single-beam low-beam or fog-light applications.

For the full breakdown, see our best 9006 Fog Light Bulb guide.

If you’re staring at a burned-out headlight and trying to decode the digits on the old bulb, here’s the plain answer. A 9006 is a common automotive halogen bulb designation that also goes by the names HB4 and P22d. These three labels refer to the same bulb type, and you’ll often see them listed together on packaging and in product specs.

It’s a single-beam bulb, designed for one function at a time rather than the dual high/low combination some other bulbs handle. That makes it a frequent choice for low-beam headlights and fog lights, depending on how your vehicle’s housing is built. This page covers what the numbers mean, the actual specs you can expect, and why checking fitment matters more than the label.

What Do The Numbers And Names Mean?

The “9006” is a standardized trade number that describes a specific bulb’s shape, base, and electrical characteristics. The same physical bulb is also sold as HB4, which is the industry designation used in many international catalogs, and P22d, which refers to the two-pin base that locks into your headlight housing.

Because these names describe the same component, you can shop for “9006” and “HB4” interchangeably, as long as your vehicle’s socket is designed for the P22d base. A word of caution: while the base may fit, the housing and beam pattern must also be matched to this bulb’s output for it to work correctly. The label alone doesn’t guarantee compatibility with your car.

9006 Bulb Specifications And Light Output

Standard OEM-style 9006 halogen bulbs share a consistent set of specifications across major manufacturers. The table below pulls together the typical specs you’ll see from leading brands like Philips and SYLVANIA.

Light output varies a bit by brand and product line. SYLVANIA’s basic 9006 lists 1,000 lumens at 3,100K, while Philips’s OEM-style 9006B1 is rated “up to 900 lm.” Upgrade halogen versions like Philips’s 9006PRB2 trade some lifespan for a brighter, whiter beam at 3,400K, which gives a crisper look on the road.

Where 9006 Bulbs Are Used

Because it’s a single-beam bulb, the 9006 is commonly fitted in two places on a vehicle: the low-beam position in headlight assemblies, and fog-light housings. Which one applies depends entirely on how the automaker designed the light unit. Some cars use a 9006 for low beams; others use it for the fog lights mounted lower in the bumper.

If you’re looking to upgrade those fog lamps specifically, there’s a tested roundup of the best options worth a look. For a practical comparison of the leading models, check out our list of the best 9006 fog light bulbs on the market.

Can LED “9006” Bulbs Replace Halogen?

LED versions sold as “9006 replacements” exist, but dropping one into a halogen housing involves more than swapping the bulb. LED products typically advertise different wattage, lumen output, and voltage ranges, and they often introduce polarity requirements and CAN-bus compatibility issues that halogen bulbs simply don’t have.

If the bulb is wired backward or the vehicle’s computer detects an unexpected load, you can get flickering, error codes, or a bulb that won’t light at all. Many LED 9006 listings are marked “polarity sensitive” or “CAN Bus compatible,” which is a signal that these are LED-specific concerns. Before switching to LED, check both the legality in your state and whether your vehicle’s optics are designed for a different light source.

Halogen 9006 bulbs also run hot by design, so handling and installation should follow the procedures in your vehicle’s owner’s manual. The glass envelope is fragile, and the bulb generates significant heat during operation.