When upgrading your car's headlights to LED, one of the most common questions drivers face is: What’s the difference between H7 and H4 LED bulbs? While they might look similar at first glance, their design, usage, and compatibility vary significantly. In this guide, we’ll explain the key differences and help you choose the right bulb for your vehicle.

 

1. Socket Type and Design

H7 LED Bulb:

Single Beam – It provides either low beam or high beam (not both).

Typically used in vehicles that have separate bulbs for high and low beams.

Has two prongs for connection.

 

H4 LED Bulb:

Dual Beam – Combines both low beam and high beam in one bulb.

Ideal for vehicles that use a single headlight bulb for both functions.

Comes with three prongs for switching between beams.

 

✅ Quick Tip: If your car uses separate lights for low and high beams, you likely need H7. If it uses one bulb for both, you probably need H4.

 

2. Beam Functionality

H4 = 2-in-1 Design

Has a built-in mechanism (usually a shutter or dual-chip design) to switch between low and high beams.

 H7 = 1 Beam Per Bulb

You'll need two separate bulbs: one for high beam, one for low beam.

 

3. Vehicle Compatibility

Bulb Type	Common Vehicles
H7	VW Golf, BMW 3 Series, Mercedes-Benz C-Class
H4	Toyota Corolla, Honda Civic, Ford Ranger

 

*** Always check your vehicle manual or OEM part to confirm the bulb type.

 

 4. Installation & FitmentBoth H4 and H7 LED bulbs come in plug-and-play designs.

However, H4 bulbs may require canbus decoders in some cars to avoid flickering or error codes.

At Watonlight, we offer 1:1 halogen-size LED bulbs that ensure a perfect fit without modification.

 

5. Which One Should You Choose?

Feature	H4	H7
Beam Type	Dual beam	Single beam
Number of Bulbs Needed	1 per headlight	2 per headlight (1 low + 1 high)
Plug Type	3 prongs	2 prongs
Best For	Simpler systems	Cars with separate high/low beam units

 

If you’re unsure, our team is happy to assist you with a fitment guide or recommend a suitable product based on your car model.

  

Need Help?

Still confused about H4 vs H7? Contact us today or send us your car make and model — we’ll help you find the perfect LED upgrade.