The H9 and H11 lightbulbs may look the same, but there are also some differences. Many motorists are wondering which bulb to choose. Are these bulbs interchangeable? What are the differences and similarities between the two bulbs?
If you’re looking for a new headlight bulb for your car and are wondering whether you need an H9 or H11, read on. This article will tell you everything you need to know about the H9 vs. H11.
| Bulb Type | H11 | H9 |
| Picture |  |
 |
| Wattage | 55W | 65W |
| Function | Headlight | Headlight |
| Interchangeable? | Only With Some Modification | |
| Need One? | See Current Price | |
H9 vs. H11 similarities
Both the H9 and H11 lightbulbs are LED’s which look almost identical. For this reason, many people think that they must be interchangeable. When comparing these two bulbs, you’ll notice that the trim tab and connector of the H9 and H11 lightbulbs look the same. Looks can be deceptive, and there are many differences between these bulbs, which means that they aren’t compatible and shouldn’t be interchanged.
H9 vs. H11 differences
Although they are similar bulbs, there are actually have different features. There are also differences in the performance of these two bulbs.
Appearance
If you look at the H9 and H11 more closely, you’ll see that there’s a slight difference in their tabs. The H9 lightbulb has an extra tab on top, which isn’t on the H11 lightbulb. The top tabs on the H9 are identical, whereas the H11 light bulb tabs are asymmetrical and opposite.
Performance
Many people think that the H11 performance is much better than the H9 as it produces a brighter light. It’s a powerful bulb that shines a bright light commonly used for driving in darker conditions or in the fog. When using an H11 lightbulbs, it’s important to dim your headlights as you meet oncoming traffic so as not to dazzle other drivers. The H9 has a shorter lifespan than the H11.
Fog lights
As mentioned above, the H11 is the best of these two lightbulbs to be used as fog lights. If you’re using an H9 lightbulb, it will fit your fog lights better with a slight modification. An H9 lightbulb will produce 1450 lumens, but if it’s been modified, this will increase to 2100 lumens. The modification would also cause a 10-watt and 2-amp increase and create a brighter light.
Trimming an H9 and H11 lightbulb
If you look carefully at these lightbulbs, you’ll notice that they both have a base that can be trimmed. Modifying a lightbulb will allow you to use it in the way you desire and allow the lightbulb to fit correctly into the headlight housing.
Both the H9 and H11 lightbulb has a base that can be trimmed to about 3mm. When trimming, cut the top tab’s left-hand side so that the headlight bulb fits snugly into the top light housing.
Cleaning and removing debris
Whichever light bulb you choose, the H9 vs. H11, you should regularly clean and maintain your lightbulb. Over time headlights can suffer from wear and tear and be affected by debris from the road surface. You can wipe down your headlights and bulbs with a soft cloth and 91% Isopropyl. This will help to clean away any debris.
Replacing H11 with H9
If you want to replace your H11 lightbulb with an H9, you can see the bulbs tab top. To do this, use a sharp blade or chisel and a rubber mallet. Many motor enthusiasts recommend replacing an H11 bulb with a modified H9 lightbulb, as this is a useful upgrade. Here’s how to do it.
We don’t really recommend doing this unless your vehicle is operated in extreme conditions that would warrant such a drastic change. If your headlights are dim, it may be that the bezel is responsible.
Conclusion
As you can see, the main similarity between the H9 and H11 lightbulbs is that they look the same. They are both LED lightbulbs that have very similar fittings. However, these two lightbulbs are very different in their performance. Many motorists who have previously used H11 lightbulbs have decided to upgrade their lights by modifying the H9. This allows them to take advantage of many of the H9’s features.