Headlight Bulbs By Size

Automotive bulbs use letter-and-number codes such as H11, H7, 9005, or 9006. These codes identify the bulb's fitting and design—not how bright the bulb is.

Use this headlight bulb size chart to compare common sizes, alternative names, and typical applications.

Important: Typical application does not guarantee fitment. Bulb sizes can vary by model year, trim, factory headlight package, and aftermarket headlight assembly.

For a more complete explanation of alternative bulb numbers, see the Car Light Bulb Size Cross Reference.

How Do I Know What Headlight Bulb Size I Need?

If you're unsure which bulb size fits your vehicle, use one of these three methods.

1. Check by Year, Make, and Model

Start with:

Year → Make → Model → Light Position

Low beam and high beam bulbs may use different sizes on the same vehicle. Vehicle trim and headlight configuration can also affect fitment.

2. Check the Owner's Manual

Your owner's manual may list replacement bulb numbers for the low beam, high beam, fog light, and other exterior lights.

Look for bulb codes such as H11, H7, 9005, 9006, 9012, H4/9003, or H13/9008.

3. Check the Existing Bulb

If you can safely remove the bulb, check the number printed or stamped on its base or housing.

This is especially useful if your vehicle has aftermarket headlights, since the required bulb may differ from the original factory specification.

What Do Automotive Bulb Numbers Mean?

An automotive bulb list can be confusing because the same bulb may appear under more than one designation.

For example:

• 9005 is also called HB3.

• 9006 is also called HB4.

• H4 may also be labeled 9003 or HB2.

• H13 may also be labeled 9008.

• 9012 may also be labeled HIR2.

These alternative names can help you recognize the correct bulb, but similar-looking bulbs are not automatically interchangeable.

Always confirm the specified bulb size for your vehicle rather than choosing a bulb based only on appearance.

Single-Beam vs. Dual-Beam Bulbs

Headlight bulb sizes can also be divided into two basic types.

Single-Beam Bulbs

A single-beam bulb normally performs one function, such as low beam or high beam.

Common examples include H11, H7, H1, 9005/HB3, 9006/HB4, and 9012/HIR2.

Vehicles using single-beam bulbs often have separate bulbs for high and low beams.

Dual-Beam Bulbs

A dual-beam bulb provides both high and low beam functions from one bulb position.

Common examples include H4/9003, H13/9008, 9004/HB1, and 9007/HB5.

This distinction can help you understand why some vehicles require two different headlight bulb sizes while others use one.

How to Choose an LED Headlight Bulb After Finding the Right Size

Once you know your bulb size, consider more than just advertised brightness.

Bulb Dimensions

LED bulbs contain cooling components that halogen bulbs do not. Check whether there is enough space behind the headlight housing or dust cover.

Beam Pattern

Higher output does not always mean better visibility.

A properly designed LED bulb should position the light source correctly so the headlight can produce a focused beam instead of excessive scattered light.

Heat Management

LED bulbs use heat sinks, fans, or other cooling systems to manage operating temperature. Effective heat management helps maintain stable performance.

Vehicle Compatibility

Some vehicles may require additional electronic compatibility solutions after an LED bulb is installed.

Always verify your exact vehicle and headlight configuration before purchase.

Find the Right Bulb Size Before You Buy

Already know your bulb number? Choose the corresponding size above and compare SEALIGHT options designed for that fitting.

Still unsure? Don't guess based only on bulb shape. Check your vehicle information, owner's manual, or the bulb currently installed.

Finding the correct bulb size first helps you avoid fitment problems and makes it easier to choose the right SEALIGHT replacement.