There has been much discussion over the interchangeable use of the H4 headlight with a 9003 headlight.
While they are technically interchangeable, US laws have interfered with the H4 use in US cars.
Let’s take a look at these bulbs to decide the best use for 9003 vs. the H4 bulb.
What’s an H4 bulb
The H4 bulb is a double filament /double beam halogen headlight used for motorcycles and offroad vehicles (race cars). It is not used as a headlight in the US as it is a high-beam light whise tolerance is too high.
What’s a 9003 bulb
The 9003 bulb is a double filament/ double beam headlight used in US cars. It serves as a high-beam and low-beam headlight that gives the driver two headlights in one.
H4 vs. 9003: Their Differences
These bulbs have a double filament, the same outer housing, and a three-prong connector. Both are considered HB2 bulbs.
A quick look
|Night driving capability||Low||High|
|Light Color||White, blue, yellow, or violet||Blue or white|
|Level of tolerance||Can affect the vision of oncoming drivers||Do not affect the vision of oncoming drivers|
|Base||Shorter third prong||All prongs have the same length|
|Compatibility||Compatible with both H4 and 9003 housings||Only fits 9003 housing|
|Price||$8 (motorcycle)||$6 (car)|
|Use restrictions in the US||Only allowed for motorcycles||Only allowed for cars|
H4 is a high output headlight.
9003 is a bright headlight that is not as bright as an H4 headlight. The light’s angle is perfect for night driving.
Types of Filament
H4 has a dual filament.
9003 has a dual filament.
Brightness of Headlamp
H4 has more lumens that makes it the brighter of the two bulbs. These bulbs give off white, blue, yellow, or violet light that is exceptionally bright.
9003 has fewer lumens than the H4, resulting in a dimmer bulb that gives off a blue, white light that is bright but not as bright as an H4 bulb.
Consumption of power
H4’s higher output uses more energy; the amount is insignificant.
9003 use less energy, but the use is barely less than the H4.
Level of Tolerance
Tolerance is based on the “Dazzle Zone,” or the area where the top of the headlights will hit the diver’s vision in oncoming traffic.
H4 is too bright; if it is not perfectly seated in the harness, it can shift and hit the dazzle zone of oncoming travelers.
9003 is set low enough not to affect drivers’ vision in oncoming traffic.
The bases are entirely different, making them non-compatible in their use.
H4’s base is three-pronged, with the third prong shorter than the other two tabs.
9003’s base is three-pronged, with all prongs being the same length.
The vibration toleration of these bulbs is not significant enough to make a decision in purchasing the bulbs. No facts back up the vibration myth at this time.
H4 is said to be more durable due to withstanding vibrations better than the 9003.
9003 Less durable as it does not tolerate vibrations as the H4.
Both have a three-prong connector; the H4 has one smaller connector, whereas the 9003’s has three same-size connectors.
H4 is compatible with both H4 and 9003 housings.
9003 only fits 9003 housing, does not fit H4 housing.
A Hella single bulb on Amazon is priced as follows:
H4 is $7.86 (motorcycle).
9003 is $5.81(car).
Blindness to Oncoming Traffic
H4 is blinding to oncoming traffic.
9003 is not blinding to oncoming traffic.
Legality in the US
H4 is legal in the US only for motorcycles.
9003 is legal in the US in cars only.
H4 is available in the US as a motorcycle headlight and in Europe for off-road vehicles.
9003 is available only as a car headlight in the US.
Where to use H4 bulbs
As a motorcycle headlight in the US, in Europe, they can be used in both motorcycles and racing cars.
Where to use 9003 bulbs
As headlight in the US.
Halogen H4 vs. LED H4
- Cheaper than an LED
- Bulb is easier to find
- Creates 5 X more heat than a LED
- Pulls more current
- Shorter Bulb life
- Produces less heat than a halogen
- Pleasing to the eye on the mororcycle or race car
- Uses less current
- Saves 30% more energy yet uses 2X more lumens
- Converts light into energy 6x more efficiently
- Can save a minimal amount of fuel
- Long bulb life
- High durability
- Cost 3X more than a halogen bulb
- Not as available as a halogen bulb
H4 vs 9003: Which one should you use?
When deciding which one you should use, you need to look at what is legal in the US for each.
The H4 is legal only as a motorcycle headlight and for racing cars in Europe.
The 9003 is legal in the US as a high-beam and low-beam headlight offering a two-for-one use.
Dimming the Lights
Understanding the use and legality of each bulb is essential to choosing which bulb you use.
While the H4 is compatible with the 9002 housing, using the bulb as a headlight on a US car is not legal.
Use the above guide when choosing the H4 vs. the 9003 headlight.