Although H11 and H11b having similar naming schemes make it seem like they would be interchangeable, but in fact, these bulbs have some differences including how they are mounted and their performance levels. As long as the light bulbs you purchase have a PGJ19-2 base and are 2 inches in diameter by 4.5 inches in length, they will be compatible with one another.

However, the primary distinction between these two types of bulbs lies in their mounting hardware. Additionally, there are also some wiring discrepancies. so, let`s start the review and contrast these two lamps.

Socket Compatibility

H11 headlight bulbs can fit into a few other types of headlight bulb sockets, but not H11B sockets. In fact, no other type of headlight bulb socket is compatible with H11B sockets. However, the H11B lamp may perfectly fit the H11 bulb socket, because they are dimensionally the same.

The truth is that when a socket is not compatible with a bulb, the connection is very loose, and the bulb may flicker or fail to light up at all. H11 has one wire that is slightly longer than the other, while both wires on the H11B are the same length. The difference in wire length exists because manufacturers design the H11B for use in specific applications where both filaments receive the same amount of power.

This is not always possible with an H11 socket, so some manufacturers will put a diode on one side of the bulb to account for this discrepancy. The diode prevents too much electricity from passing through to one filament, which would cause it to burn out quickly.

H11 bulb explanation

H11 is a very common option among automotive light bulbs. It is used in a number of applications, such as headlights, fog lights, and daytime running lights (DRLs). The H11 bulb has a PGJ19-2 base, which means it can be used in place of other types of bulbs with the same base. The most notable difference between H11 and other types of bulbs is its filament life.

H11 bulbs have a briefer filament life of approximately 270 hours. On the contrary, filaments in H11b headlights last about 930 hours - more than three times as long as those in regular H11 bulbs. Of course, the longer the lifespan of a filament, the better.

Overall, the H11 lamp is perfect when you drive in the city or in a short distance. It does not produce dazzling light that can disrupt oncoming traffic.

H11B bulb explanation

H11B is a type of headlight bulb that is manufactured by only a few companies, such as Hyundai and Kia. The most notable difference between H11 and H11b headlight bulbs is the filament's life or lifespan.

They are appreciated by the drivers who frequently replace their headlight bulbs. The filaments in H11b headlights last about 930 hours - more than three times as long as those in regular H11 bulbs. Of course, the longer the lifespan of a filament, the better. With H11b bulbs, you don't have to frequently replace your headlight bulbs.

In terms of light output, H11 and H11b headlight bulbs are pretty much the same. They both produce about 1250 lumens of brightness. The beam pattern is also identical. There is no difference in the light distribution between these two types of bulbs.

Specifications Comparison


H11 utilizes a 55w halogen headlight bulb and creates around 900 – 1,000 Lumen of light with a typical yellowish hue. Moreover, it needs a voltage of 12v to function. On the other hand, H11B is also a 55w headlight bulb that emits around 1,200 Lumen of light but with a whiter and brighter shade. Even though it requires the same amount of power, it functions better due to its design.

Beam Type

H11 headlight bulbs are usually used for fog lights or other similar front car lights, whereas H11B headlight bulbs are designated to be low beam headlights. These two types of lightbulbs cannot be swapped due to their dissimilar functions. So, in case you accidentally bought an H11B instead of an H11, it would be best to take it back to the store and have it replaced.


In H11 headlight bulbs, the return wire is placed next to the widest tab, which is at the bottom of the ring. However, in H11b headlight bulbs, the return wire is placed opposite the widest tab - located at the top of said ring. If you were to try and use these headlights interchangeably by making adjustments, then the wire would drop down interfering with the lightbulb and creating a shadow visible in your line of sight; this essentially reduces performance and efficacy.


H11 headlight bulbs usually have a lifespan of between 450 and 500 hours, whereas H11B’s lifespan is around 900 hours. This difference in lifespan is due to the fact that H11B has a double-coil filament, which can withstand higher temperatures.

Usage cases

So, where do you use H11 and H11B bulbs? In fact, there are a few key differences in usage. H11 bulbs are mostly used for fog lights, while H11B bulbs are used as low beam headlights. H11 bulbs have a yellow light, while H11B has a white light. Drivers also try to use H11B in place of H11 bulbs for fog lights, but this is not recommended as it can create a shadow in your line of sight.

What Bulb Should I Buy?

When choosing between H11 and H11B, the decision comes down to personal preference and your car. If you have a car that uses H11 bulbs, then you can safely buy either H11 or H11B bulbs. Both types will fit in the socket and they have the same light output.

Your choice will depend on your purpose. In case a driver needs to frequently replace his bulbs, then H11B is the better choice because its filaments have a much longer lifespan. On the other hand, if you don't mind replacing your bulbs every now and then, H11 bulbs are a good option because they are cheaper.

It's also worth mentioning that H11B headlight bulbs are not as common as H11 bulbs. So, if you need to replace your headlight bulbs, it might be difficult to find H11B bulbs. In this case, H11 would be the better choice because it's more widely available. For example, in case you desire to replace the signaling lights in your vehicle, H11B will not be a good option as it is not available as commonly as the H11 bulbs. And for those, who desire to replace the brake lights, the same goes. The H11B lamps would be a perfect solution if you want to replace the headlights.

All in all, it depends on your needs and preferences. If you need to frequently replace your headlight bulbs, go for H11B. If you don't mind replacing them every now and then, H11 is a good option. And if you need to replace other types of bulbs in your car, H11 is the better choice because it's more widely available.

In conclusion, H11 and H11B headlight bulbs are very similar. They have the same base, the same size, and the same light output. The only significant difference between them is their lifespan. H11B bulbs have longer-lasting filaments, which means they will last longer before needing to be replaced. However, H11 bulbs are more widely available and they are usually cheaper. Therefore, the choice between H11 and H11B comes down to personal preference.

Reviewed by Brent Ordway

Brent Ordway is an ASE-certified car technician. He has been working on cars since he was a teenager and loved helping people keep their vehicles running smoothly. Brent's skills as a mechanic are unrivaled. In 2022, he earned his place on the list of winners for the ASE Master Automobile Technician of the Year award.

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