9003 vs H4
The 9003 and H4 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 9003 is found in 19 vehicles, commonly in the High Beam position, while the H4 appears in many vehicles, typically used for various positions. 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 9003
19
Vehicles Using H4
0
Use Both
0
Specification Comparison
| Feature | 9003 | H4 |
|---|---|---|
| Mount Type | spring clip retainer with a three-prong base identical to H4 | spring clip retainer with a three-prong base |
| Dual Filament | Yes (dual filament) | Yes (dual filament) |
| Interchangeable | Yes, fits H4 socket | Yes, fits 9003 socket |
| Also Known As | H4, HB2 | HB2, 9003 |
Can You Swap 9003 and H4?
The 9003 and H4 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 9003 but you can only find H4, it will fit and work safely. When upgrading to LED, look for a kit that lists both 9003 and H4 compatibility.