What’s The Difference Between Headlights And Fog Lights?

As car owners, you and I have thought about the purpose of fog lights. Why are fog lights there, and what can they do that headlights cannot?

While headlights are the primary light source for your car in the dark, fog lights have a specific role. They are not the same when compared to regular headlamps.

Let’s get into the difference between fog lights and standard headlights. I will cover every aspect where they differ from each other while providing an in-depth explanation.

A brief comparison between headlamps and fog lamps

In a hurry? Let’s have a look at a short comparison table for understanding the basics:



Fog Lights


Primary illumination

Secondary illumination and assisted lighting during rain or fog


Front end of the vehicle

Under regular headlights


2000-4000 on average

1200-2000 on average


Does not work well during fog or rain

Cannot be used as a primary source of illumination


Larger by size

Usually smaller compared to regular headlight bulbs


Headlights are required by law in the US

Fog lights are optional by law in the US


Usually square



Long, upfront/forward

Short, angled downwards


What are headlights?

Headlights are the primary source of illumination or light in a car. It is a pair of lighting systems that can be found in front of the vehicle. Headlights provide vision in dark areas and are mandatory by law.

Headlights are usually comprised of:

  • A housing – reflector or projector
  • One or more bulbs – LED, Halogen, or Xenon

What are fog lights?

Fog lights are situated below regular headlights right on the bumper of the car. These lights have low brightness but high penetration. Angled downwards to the road, they provide the driver a clear vision of the front without blinding oncoming vehicles.

Fog lights used to be yellow to have a high penetrating beam. However, a lot of fog lights nowadays are available in bright white. Even so, I recommend yellow ones because they work better under foggy weather.

Fog lights can improve vision during:

  • Fog
  • Smoke
  • Rain
  • Dust
  • Snow
  • Storms


During foggy, rainy, or snowy weather, the light of regular headlights become ineffective. It’s because the light from a high or low beam headlight bounces off of the moisture in the air. Therefore, instead of providing illumination, it blinds the driver and makes it hard to see what’s in front of them.

Fog lights are used in such weather conditions mentioned above. They are angled downwards to the road and have more penetration. As a result, fog lamps provide good visibility during bad weather and dust.

A downward angle makes the fog lights suitable for foggy and rainy weather. However, that’s the same reason why fog lights cannot be used in replacement of regular lamps. It can only illuminate a few meters in front of you but not more than that!


Regular headlights tend to have more brightness than fog lamps. Here’s a table of the lumen outputs of different types of car headlights:


25 Lumens/Watt


75-110 Lumens/Watt


120 Lumens/Watt

Usually, 55 Watts is the standard wattage used in car headlight bulbs.

On the other hand, Fog lights are rated at 35 Watts. Thus, they tend to have a lower lumen output compared to regular headlamps.


Headlights are required by law! So, all cars come equipped with them.

Fog lights are not mandatory by law. Moreover, you cannot use fog lights to replace regular headlights.

In some states, fog lights can only be used in critical conditions. It means some state laws prohibit the usage of fog lights in stable weather conditions. You can only use them when vision is impaired due to fog or heavy rain. This is done to reduce the glare caused by fog lights on oncoming drivers.

What are the primary differences between fog lights and headlights?

  • Headlights are primary lights for automobiles and are mandatory by law. On the other hand, fog lights are an optional source of illumination for assisted light.
  • The color temperature of headlights tends to be light yellow to white. Yet, most drivers prefer yellow fog lights for better fog penetration.
  • There is a visible size difference between headlights and fog lights, even though they often can look the same.
  • Headlights can’t provide optimal performance during rain or foggy weather. A downward beam of fog lights can help in these situations to see well.
  • Fog lights are usually on the bumper, under headlights. Regular headlights are generally situated
  • on the center of the front of the vehicle.

Fog Lights

Here’s a video explaining it:

Do all cars have fog lights?

Many new cars do not have fog lights.

Are fog lights and headlights the same bulb?

A lot of the time, fog lights and headlights can have the same bulb. Sometimes, there is a wattage difference between fog lamps and regular lights of a car.

Final Note

As you can see, there are significant differences between standard headlights and fog lights. However, the most important distinction is how fog bulbs can improve your vision during rainy and foggy weather. As a result, if your car doesn’t already have fog lights, installing them is a good idea.

I have already written about good fog lights on the market. Nonetheless, I’m interested to know what kind of fog light you use and if it’s good or bad. Let me know in the comments!

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