What is the single most important thing to get right when buying headlight bulbs?

Your bulb size. Automotive headlight bulbs are sized by a code — H11, 9005 (also called HB3), H7, 9006 (HB4), H4 and so on — and a bulb in the wrong size simply will not fit or focus. The size is printed on your old bulb, in your owner’s manual, and in the online fitment lookup every retailer offers. Confirm it before you spend a dollar. Our headlight bulb size guide walks through finding it, and every ranking on this hub tells you to check it first, because the number-one reason lighting purchases get returned is a size mismatch.

Are aftermarket LED headlight bulbs actually legal?

It is a genuine grey area, and we do not pretend otherwise. LED replacement bulbs are not DOT-approved for use in halogen reflector housings, and in a reflector they can throw a scattered beam that glares oncoming drivers even while looking brilliant to you. In a projector housing they behave far better. Most are sold labeled "off-road use only" for exactly this reason. Whether police enforce it varies by state and by how much glare your setup produces. We cover the whole picture honestly in are LED headlight bulbs legal so you can make an informed call.

Do the "30,000 lumen" brightness numbers on LED bulbs mean anything?

Not really — treat the giant lumen claims as marketing. A pair of physical LED bulbs cannot produce the five-figure lumen totals printed on many boxes; independent measurements land far lower, and a claim per-pair, per-bulb or theoretical-chip-maximum is rarely stated. What actually matters is beam pattern (a sharp cutoff that lights the road, not the sky), color temperature (6000K is a clean white most owners prefer), and real-world owner reports of usable down-road light. We rank on those, not on the lumen sticker, which is why our picks are the ones owners keep praising after a year rather than the ones with the biggest number.

Are light bars and underglow street legal?

Rules vary by state, but the safe generalizations hold up. Off-road light bars are legal to mount but generally must be covered or switched off on public roads — they are auxiliary lights for the trail, not extra headlights for the highway. Underglow is restricted in many states, and where allowed it usually cannot be red or blue (colors reserved for emergency vehicles), cannot flash, and cannot be lit while driving in some jurisdictions. Check your state before installing either. Our light bar and underglow rankings flag the legal considerations for each.

How do we rank automotive lighting?

We do not run a photometric lab or a test track. We rank by aggregating thousands of owner reviews, star ratings, review volume and price-to-value across each category, then weigh in the consensus from enthusiast forums and installers. A product has to earn a strong rating across a large base of real buyers — not a handful of glowing early reviews — to reach the top. For lighting specifically we lean hard on repeated owner reports of beam quality, fitment accuracy and longevity, because those are what separate a bulb that still works next winter from one that flickers out. Prices and picks reflect what the reviews actually support.

Automotive Lighting: LED Bulbs, Light Bars & Fog Lights

Bulbs · Light Bars · Fog Lights · Underglow

Written & researched by Taryn Walsh DIY Repair & Tools Editor

Updated June 2026

Affiliate Disclosure

Some links on this page are affiliate links. As an Amazon Associate, we earn from qualifying purchases — at no extra cost to you. We do not buy, test, or physically handle the products we cover; our rankings come from aggregated owner reviews, ratings and expert consensus. Commissions never change our verdicts. How we rank & full disclosure.

Short version: your headlights are a safety system you probably never think about until you are squinting down a dark road wondering why you can barely see. Better lighting is one of the cheapest, most noticeable upgrades you can make to any car or truck — but it is also the category most riddled with inflated claims, fitment traps and legal grey areas. This hub ranks every type of automotive lighting by aggregated owner ratings, review volume and value, and it tells you the honest truth about bulb sizes, lumen hype and legality that the product boxes will not. No lab theatrics — just what thousands of drivers actually report living with.

Automotive lighting splits into two jobs: seeing the road and being seen. Seeing is your headlights and fog lights — the bulbs that put usable light where you are driving. Being seen (and, honestly, being noticed) covers auxiliary light bars for off-road work and underglow for looks. Different jobs, different rules, one shared first step: know your bulb size before you buy anything. Here is how the whole category fits together, and where to start.

Headlight Bulbs: The Upgrade Everyone Notices

If you buy one lighting upgrade, make it your headlight bulbs — they are what you actually drive by. You have two honest paths. A halogen upgrade bulb (SYLVANIA SilverStar, Philips X-tremeVision) is a guaranteed-legal, drop-in replacement that pushes a standard bulb’s output and whiteness as far as the technology allows. An LED conversion bulb (SEALIGHT, Fahren, Hikari) is dramatically brighter and whiter and lasts far longer, but lives in a legal grey area in reflector housings. We rank the pure-LED field in best LED headlight bulbs, the whole halogen-plus-LED picture in best headlight bulbs, and settle the technology debate in LED vs halogen headlights. Whichever you choose, the swap is a 15-minute driveway job — how to replace a headlight bulb covers it.

Bulb Size: The One Thing That Ruins More Purchases Than Anything Else

Before any of the rankings matter, you need one piece of information: your bulb size. Headlight bulbs come in fixed sizes — H11, 9005 (HB3), 9006 (HB4), H7, H4/9003, 9012 and a handful more — and they are not interchangeable. A 9005 will not seat in an H11 socket, and ordering the wrong one is the single most common reason a lighting purchase comes straight back. Your size is molded into the base of your current bulb, listed in the owner’s manual, and searchable in any retailer’s fitment tool. Many vehicles even use different sizes for low beam, high beam and fog. The headlight bulb size guide is the page to read first — it is the fitment lookup the rest of this hub links back to constantly.

Fog Lights: Cutting Through Weather (and the Lumen Hype)

Fog lights sit low and wide to throw a flat beam under fog, rain and snow — the conditions where a high headlight beam just bounces glare back at you. Upgrading them is popular because the improvement is so visible, but fog bulbs have their own size (often H11, H10/9145 or 9006, and not always the same as your headlights), so the size warning applies double. LED fog bulbs run cool, last for years and throw a crisp white or selective-yellow beam owners love. We rank the field, and flag the fitment and beam-pattern gotchas, in best LED fog lights. As with all LED conversions, remember that the giant lumen numbers on the box are marketing — beam quality is what earns the top spots.

Light Bars: Auxiliary Power for Off-Road

A light bar is a different animal entirely — an auxiliary light for the trail, not a headlight for the highway. Mounted on a roof, bumper or grille, it floods the trail ahead with far more light than any headlight, which is exactly why most states require it covered or switched off on public roads. The market runs from excellent-value combos (Nilight, Auxbeam) to premium overlanding bars (Rigid Industries, Baja Designs) built to survive years of vibration and weather. Truck owners get a dedicated ranking in best light bar for truck, and the full field — single-row, dual-row and pods — is ranked in best LED light bar. Match the bar to real use: a flood pattern for close trail work, a spot for distance, a combo for both.

Underglow and Styling: Being Seen, On Purpose

Not every lighting upgrade is about seeing the road. Underglow lights are app-controlled RGB strips mounted under the body for pure style, and the modern kits do a lot — 16-million-color control, music sync, chasing effects — for surprisingly little money. The honest caveats are legal (many states restrict color, flashing and driving-while-lit — red and blue are almost always off-limits) and installation quality (the cheap adhesive-only kits fall off; owners who add proper mounting keep them for years). We rank the kits owners trust to actually stay stuck on and keep working.

Where to Start

Build your lighting the way it matters. Start by confirming your bulb size, then upgrade the lights you drive by — headlight bulbs first, fog lights next. Add a light bar only if you actually go off-road, and treat underglow as the styling flourish it is. Every ranking below leans on aggregated owner ratings, review volume and value, and every one tells you the fitment and legality truth up front. And when your old lenses have gone cloudy and yellow — no bulb fixes that — the headlight restoration hub and the glass and visibility hub pick up where this one leaves off.

Automotive Lighting: See More, Be Seen