How do I know what headlight bulb size my car uses?

Check the owner's manual, read the size code off the old bulb (e.g. H11, 9005, 9006, H7), or look it up by your year, make and model. The size must match for the bulb to seat and aim correctly. You can also ask AXLY for the bulb size for your specific vehicle.

Can I touch a new headlight bulb with my fingers?

Avoid touching the glass of a halogen bulb — the oils from your skin create hot spots that can crack it or shorten its life. Hold it by the plastic base. If you do touch the glass, wipe it clean with rubbing alcohol before installing.

Are LED headlight bulb upgrades legal?

It varies by region — some LED retrofit bulbs are sold as off-road/show use only and may not be street-legal everywhere. Choose a kit with a proper beam pattern, aim it correctly so you don't blind oncoming drivers, and check your local rules.

Should I replace both headlight bulbs at once?

It's a good idea. Bulbs from the same set age at a similar rate, so when one burns out the other is usually close behind. Replacing both keeps your beam output even side to side and saves a second job soon.

Why does my headlight keep burning out?

Frequent burnouts can come from touching the glass during install, moisture in the housing, excess vibration, or a charging-system issue sending too much voltage. If bulbs fail unusually fast, check for condensation in the housing and have the charging voltage tested.

How to Change a Car Headlight Bulb (in About 15 Minutes)

A burned-out headlight is a quick, cheap fix that most people can do in their driveway in about 15 minutes — no mechanic required. Here’s how to swap a bulb the right way, and whether a brighter LED upgrade is worth it.

What you need

Just the replacement bulb in the correct size, and maybe a clean rag and rubbing alcohol. If you’re already in there, it’s the perfect time to upgrade aging halogens to brighter, whiter LED bulbs — a popular, affordable pick is a set of LED headlight bulbs in your fitment. To pick the right ones (and understand beam pattern and legality), see our guide to the best LED headlight bulbs.

Step-by-step: how to change a headlight bulb

Find your bulb size. Read it off the old bulb or your manual (H11, 9005/HB3, 9006/HB4, H7, etc.). Not sure? Ask AXLY the headlight bulb size for your exact year, make and model.
Open the hood and find the housing. Locate the back of the headlight assembly — a round dust cap or the bulb’s wiring connector. Some cars need a cover removed for access.
Disconnect and remove the old bulb. Unplug the connector, release the bulb (a quarter-turn, clip, or twist-lock), and pull it straight out.
Install the new bulb — don’t touch the glass. Handle it by the plastic base only. If you touch the glass, wipe it with rubbing alcohol. Seat it, lock it, and replace the dust cap.
Reconnect and test. Plug it back in and confirm low and high beam both work.
Check the aim. Face a wall ~15 feet away and make sure the beam sits at a sensible height and isn’t blinding oncoming traffic.

Where AXLY helps

The fiddly part is usually just knowing the exact bulb your car takes. AXLY.pro is a free iPhone app built around your specific vehicle — Ask AXLY the bulb size (or any other spec) for your year, make and model and get a straight answer instead of guessing in the parts-store aisle. And if a bulb or lighting circuit ever throws a trouble code, AXLY reads and explains it. Download AXLY.pro free on the App Store.

Ready to see the road better? Compare brightness, beam pattern, and fitment in our roundup of the best LED headlight bulbs.

As an Amazon Associate, AXLY earns from qualifying purchases — at no additional cost to you. Product links in this article are affiliate links; we only recommend gear we believe pairs well with the app.