Choosing the right bulb size for your vehicle's headlights or fog lights can be confusing. Halogen, LED, and HID bulbs come in many sizes referenced by a part number or "bulb number". The tricky thing is that different manufacturers like Sylvania, Philips, and Hella may use their own part numbers for the same bulb.

So when you go to replace a halogen bulb with an LED, the size in your owner's manual might not match what you find online. Many bulbs have the same base and connectors but are called different part numbers.

To make things easier, here's a handy cross-reference list of the most common bulb bases split up by light type - headlight, fog light, backup light, brake light, etc. Use this to match your bulb to the right LED replacement.

Headlight Bulb Size Cross Reference

Headlight bulbs are located on the front of the car to illuminate the road ahead. They can be high beams for further illumination or low beams for normal driving. Below is some of the most common headlight bulb sizes and their cross reference numbers:

Quick Tips:

Dual-filament bulbs (like H4, H13, 9004, 9007) can function as both high and low beams.

Single-filament bulbs (like H11, 9006, H7) are usually dedicated to one beam type.

Always consult your vehicle’s manual or a trusted parts guide before purchasing replacements.

Cross-reference numbers help identify interchangeable bulbs even if part numbers differ by brand or region.

Fog Light Bulb Size Cross Reference

Fog light bulbs are mounted low on the front bumper to help illuminate the road better in foggy or misty conditions. They provide a wide, bar-shaped beam of light to cut through low visibility. Usually have a white or yellow tint.

Common bulb sizes used for backup lights include the following, along with compatible replacements:

Quick Notes:

H16 Confusion: There are two types of H16 bulbs:

H16 (T-Shaped): Often used in 5202/PSX24W applications.

H16 (Standard): Interchangeable with H8/H9/H11.

Beam Pattern: Fog lights are designed to produce a wide, low, and bar-shaped beam, cutting through fog, mist, and snow without reflecting into the driver's eyes.

Back Up light Bulb Size Cross Reference

Backup light bulbs are mounted on the rear bumper or around the license plate. They automatically turn on when the vehicle is shifted into reverse gear. Here are some typical backup light bulb sizes and their compatible replacements:

Brake Light Bulb Bulb Size Cross Reference

Brake light bulbs are located at the rear of the car and illuminate when the brakes are applied to alert other drivers the car is slowing down. Below is some common bulb sizes used for brake light and their cross reference numbers:

Tail Light Bulb Bulb Size Cross Reference

Tail light bulbs are red lights mounted on the rear of the car illuminated when headlights are on to mark the back of the vehicle. Here’s the list of some common bulb sizes for tail light bulbs and their cross-references numbers:

Turn Signal Light Bulb Bulb Size Cross Reference

These handy blinking lights, positioned on the front and back corners of your car, illuminate when you're making a turn or changing lanes. When replacing burnt-out bulbs, you'll likely come across these common turn signal bulb sizes and their interchangeable model numbers:

Center High Mount Stop Light Bulb Size Cross Reference

Center High Mount Stop Light Bulb Also called a third brake light. An additional brake light mounted higher in the rear window to further indicate braking. Some common bulb sizes and corresponding cross references include:

Other Car Light Bulb Size Cross-Reference:

When it comes to your car's interior lighting, there are many different bulbs at work to illuminate the cabin. From map lights overhead to glove box lights inside, you've got dome lights, license plate lights, instrument panel lights, interior door lights and more. Here is the consolidated equivalent bulb list:

FAQs about Automotive Bulbs Cross Reference

How do I find the correct part number for my headlight or fog light bulb?

There are three types of part numbers you might come across:

Trade Numbers: These are standard codes like 9006 or H11, usually printed directly on your original bulb. They refer to the bulb's shape, size, connector type, and power usage.

Manufacturer Part Numbers:These are specific to your vehicle’s brand and are often used in dealership or OEM catalogs. They can be cross-referenced to match standard trade numbers.

Aftermarket Part Numbers:These are used by parts manufacturers and help you match a replacement bulb—like an LED—to your original halogen or HID setup.

At SEALIGHT, we base our LED bulb part numbers on these original trade numbers. The big advantage with LED bulbs is flexibility—they can often replace multiple bulb types.

For example, our H11 LED bulb can safely replace H8, H9, H11, and H16 bulbs because:

It uses less power than even the lowest-watt halogen bulb in that group.

It still shines brighter than the highest-wattage ones.

So even if there are small differences between halogen bulbs, those don’t affect LED compatibility. Our chart helps you match your vehicle’s bulb type with the correct SEALIGHT LED replacement quickly and accurately.

How do I find the correct LED bulb for my taillights, brake lights, or turn signals?

Finding the right LED bulb is simple if you follow two steps:

Check the Number on the Bulb:
Look at your original bulb. Most will have a number printed on the base or on the side of the housing. That number is the key to identifying the correct replacement.

Compare the Size:
After finding the bulb number, measure the bulb itself. Compare its shape and size with the LED bulbs you’re considering to ensure a proper fit.

Can using an equivalent bulb damage my headlight assembly?

It depends on the type of bulb you're using:

Halogen Bulbs: Swapping in an “equivalent” halogen bulb with a different wattage can cause problems. Higher wattage bulbs can overheat your headlight or fog light housing and may even damage wiring.

LED Bulbs: LEDs use much less power and run cooler than halogen bulbs. That means using an LED equivalent (like replacing H8, H9, H11, or H16 with a single H11 LED) won’t put your assembly at risk.

So if you're upgrading to LED bulbs, you're not only getting better light, you’re also reducing the risk of heat damage.

Find the Right Replacement Car Bulb Easily

Replacing a car bulb doesn’t have to be complicated. With so many sizes and types available, finding the right one for your vehicle can feel overwhelming. SEALIGHT is here to make the process simple and straightforward.

If you want to understand common bulb sizes, start with our bulb size guide collection. It breaks down the most popular sizes and explains where they are typically used. For those moments when you’re unsure about a specific bulb—like deciding between H11 and 9005—our car bulb size comparison guides make it easy to see the differences and choose the right option.

Thinking about upgrading to LED headlights but don’t know which one to pick? Our LED buying guides walk you through the key factors to consider, from brightness and beam pattern to durability and compatibility. These tips ensure you pick a bulb that not only fits but also performs safely and efficiently.

For an even faster solution, the SEALIGHT Vehicle Bulb Finder Tool lets you find the exact bulb your car needs in seconds. Simply enter your vehicle’s make, model, and year, and you’ll get a curated list of compatible bulbs ready for purchase.

Once you know which bulb you need, upgrading is just a click away. You can shop for headlight bulbs, fog light bulbs, brake and tail lights, backup and reverse lights, or turn signal lights. No matter which position you’re upgrading, SEALIGHT helps make the process fast, easy, and reliable.