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When shopping for LED headlight bulbs, you’ve probably come across the terms “single beam” and “dual beam”.
These refer to two different types of headlight bulbs. Because car lighting systems can vary from one model to another, it’s important to know how your headlight system works before making a purchase—this ensures you get the right bulb for your vehicle.
Still, many car owners are left wondering: What’s the difference between single and dual beam headlight bulb? Is H4 a single or dual beam? Does “single beam” refer to the bulb or the headlight assembly?
In fact, it’s not uncommon for customers to mistakenly buy a dual beam bulb for a headlight housing that only supports single beam.
In this blog, we’ll walk you through the key differences between single beam and dual beam headlight bulbs, how they work, and which one is right for your car. We’ll also answer some of the most frequently asked questions to help you avoid confusion when upgrading your headlights.
Single Beam vs Dual Beam: Main Difference Compared
Features | Single Beam Headlight Bulb | Dual Beam Headlight Bulb |
|---|---|---|
Light function | either low beam or high beam | both low and high beam in one bulb |
Numbers of filament | One | Two |
Total headlight bulb in a car | Four | Two |
Headlight design | Separate bulbs for each function | One bulb switches between high and low beams |
Common Bulb Types | H1, H7, 9005, 9006, H8/9/11 | H4, 9004, 9007, H13 |
Cost | Lower | Higher |
Halogen | Yes | Yes |
LED | Yes | Yes |
HID (Xenon) | Yes | Yes |
Typical Use | Cars with separate high and low beam housings | Cars with combined beam housings |
What is a Single Beam Headlight Bulb?
A single beam headlight bulb is designed to emit only one type of beam—either a low beam or a high beam, but not both.
Vehicles that use single beam bulbs require two separate bulbs per headlight: one for low beam and one for high beam.
This type of setup is common in cars with separate reflector housings for each function. Single beam bulbs are typically labeled as H1, H7, H11, 9005, or 9006, and they offer precise light control for each beam type.
When the headlights are turned on, one of the headlight bulbs lights up while the other goes out, when you switch from low to high, the low beam turns down and the high beam turns on.
Each headlight assembly has its own specific bulb size and headlight system, if you install a dual beam light bulb for a single headlight assembly, it simply won’t work and will damage your headlight bulbs.
Main Features of Single Beam Headlight Bulb:
- One bulb = one beam (either low or high, not both)
- Typically requires two separate bulbs per headlight—one for low, one for high
Example of Single Beam Bulb:
- H7 - Common for low beam in many European and Asian cars.
- H1 - Typically used for high beam or fog lights.
- 9005 (HB3) - Usually high beam.
- 9006 (HB4) - Typically low beam.
- 9012 - Low beam in projector.
- H8/H9/H11 - Used in both low beam and fog light setups.
What Type of Headlight Assembly Requires Single Beam Bulb?
A headlight assembly that requires a single beam bulb is designed to use separate bulbs for low beam and high beam functions. This means each beam has its own dedicated reflector or projector housing.
Many older vehicles, trucks, and motorcycles utilize separate headlight bulbs for low and high beams, also known as dipped and main beams. These vehicles use a single-filament bulb for each beam, requiring two separate bulbs in the headlight housing.
What is a Dual Beam Headlight Bulb?
A dual beam headlight bulb is designed to produce both low beam and high beam from a single bulb.
It uses either two filaments (in halogen bulbs) or a mechanical or electronic switch (in LED or HID bulbs) to alternate between the two beam patterns.
Dual beam bulbs are convenient because they only require one bulb per headlight housing, simplifying installation and design.
Common types include H4, 9004, and 9007. They’re widely used in vehicles with combined reflector systems.
Main Features of Dual Beam Headlight Bulb:
- One bulb = both low and high beam functions
- Often uses a mechanical shutter or dual filaments to switch beams
Example of Dual Beam Bulb:
- H4 - Very common in motorcycles and older cars. Contains two filaments for low and high beam.
- 9004 - Used in some American vehicles.
- 9007 - Similar to 9004 but with different pin configuration and improved brightness.
What Type of Headlight Assembly Requires Dual Beam Bulb?
A headlight assembly that requires a dual beam bulb is designed to handle both low beam and high beam functions from a single bulb.
Many modern vehicles come equipped with “combo headlights,” which combine both high and low beam functions into a single housing.
These integrated systems often include extra features like LED daytime running lights or turn signals for added convenience and style.
Well-known automotive brands such as Honda, Mercedes-Benz, Toyota, Audi, and BMW frequently use this type of headlight design in their newer models, offering drivers improved functionality and a sleek, unified appearance.
High Beam vs. Low Beam
High beam and low beam are also important when discussing single beam and dual beam headlights. Both high beam and low beam are legally required by transportation regulators worldwide.
As previously explained, single beam headlights use separate bulbs for high and low beams, while dual beam headlights generate both beams from a single bulb.
For more insights on this subject, you can check out our earlier blog post: High Beam vs. Low Beam: When Should We Use Them While Driving?
Single Beam vs. Dual Beam: Which One Does Your Car Use?
To find out whether your car uses a single beam or dual beam headlight bulb, start by checking your owner’s manual or looking up your car’s bulb type online.
Common single beam types include H7, H11, and 9005, while H4 is typically dual beam.
If you’re unsure, this guide can help: H4, H7, H11, 9005 | How to Identify Headlight Bulb Socket?. When upgrading to LED, always match the bulb type to your car’s headlight system for proper fit, brightness, and beam pattern.
FAQs
What’s The Key Difference Between Single Beam And Dual Beam Headlight Bulbs?
Single beam bulbs have one function per bulb—either high beam or low beam. Dual beam bulbs combine both high and low beam functions in a single bulb.
Is an H7 Bulb Single Or Dual Beam?
H7 is typically a single beam bulb, providing either high or low beams, but it’s most commonly used for low beams.
Is an H4 Bulb Single Or Dual Beam?
H4 is typically a dual beam bulb, providing both high and low beams in one.
Can I Use a Dual Beam Bulb In a Single Beam Headlight Assembly?
No. A dual beam bulb won’t work properly in a single beam housing. You must match the bulb type to the headlight assembly design.
How Do I Know Which Type My Car Uses?
Check your owner’s manual, or refer to the guide here: H4, H7, H11, 9005 | How to Identify Headlight Bulb Socket?
Are Single Beam Or Dual Beam Headlights Better?
It depends on your vehicle. Dual beam setups are more compact, but single beam systems may offer better beam control and allow for easier customization.
Is Single Beam Headlight Bulb Brighter Than Dual Beam?
Under the same lumen and wattage, single beam headlight bulbs are generally a bit brighter. That’s because they have fewer circuit components, allowing for more efficient light output. However, some brands like NAOEVO have engineered their dual beam LED bulbs to maintain higher wattage and brightness than most competitors, closing the gap significantly.
