H11 vs H9
The H11 and H9 are physically interchangeable bulb types that share the same base and socket design. Both bulbs fit the same housing, making them direct substitutes in most applications. The H11 is found in 1,323 vehicles, commonly in the Fog Light and Low Beam position, while the H9 appears in 134 vehicles, typically used for High Beam and Low Beam. Although they fit the same socket, there may be minor differences in wattage or light output between the two. Below we break down the specifications, compatible vehicles, and practical swap guidance to help you choose the right bulb.
Vehicles Using H11
1,323
Vehicles Using H9
134
Use Both
79
Specification Comparison
| Feature | H11 | H9 |
|---|---|---|
| Mount Type | quarter-turn bayonet mount that locks with a short twist | quarter-turn bayonet mount similar to H11 |
| Dual Filament | No (single filament) | No (single filament) |
| Interchangeable | Yes, fits H9 socket | Yes, fits H11 socket |
| Also Known As | H8, H9, H16 | H11, H8 |
Can You Swap H11 and H9?
The H11 and H9 share the same physical base and socket type, which means you can use either one in a housing designed for the other. However, there may be slight differences in rated wattage or light output between the two. For the best results, use the specific bulb type listed in your vehicle's owner's manual. If your manual specifies H11 but you can only find H9, it will fit and work safely. When upgrading to LED, look for a kit that lists both H11 and H9 compatibility.
Vehicles Using Both H11 and H9
We found 79 vehicles that use both H11 and H9 bulbs in different positions. Common makes include Aston Martin, Audi, Buick, Cadillac. These vehicles typically use one bulb type for the low beam and the other for the high beam or fog light, so you may need both sizes when doing a full lighting upgrade.
Showing 20 of 79 vehicles.