Headlight Bulbs Guide
Last updated: 24 April 2026
Headlight bulbs are essential for safe driving in low-light conditions. Halogen, xenon (HID), and LED technologies each offer different beam patterns, colour temperatures, and lifespans. A failed bulb is an MOT failure and a road safety hazard. At CarParts247 we stock all major bulb types from Philips, Osram, Bosch, and other trusted brands so you can find the right fit for your vehicle.
Choosing the right headlight bulb
Vehicles use different bulb fittings — H1, H4, H7, H11, and many more. Always check your vehicle handbook or remove the existing bulb to confirm the type before ordering.
- H4 bulbs combine dipped and main beam in one unit — common on older vehicles
- H7 single-filament bulbs are the most popular fitting on modern cars
- H1 bulbs are typically used for main beam or fog lights
- Xenon/HID bulbs (D1S, D2S, D3S) require a ballast unit — don't mix with halogen
- LED retrofit bulbs offer longer life but check road-legality in your country
When to replace headlight bulbs
Halogen bulbs typically last 500-1,000 hours; xenon bulbs 2,000-3,000 hours. Brightness fades gradually, so both bulbs may appear fine while delivering significantly less light.
- One bulb blown — replace both sides for even light output
- Yellowing or dimming headlights — bulbs lose up to 20% brightness before failure
- MOT advisory for dim or misaligned headlights
- Flickering on startup (xenon) — ballast or bulb nearing end of life
Category page
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Frequently Asked Questions
What type of headlight bulb do I need?
Check your vehicle handbook for the correct bulb type (H1, H4, H7, etc.). Different vehicles use different fittings — always match the exact specification.
Can I upgrade to LED headlight bulbs?
LED retrofit bulbs are available but may not be road-legal in all countries. Check local regulations before fitting. Factory-fitted LED headlights are fine.
Should I replace headlight bulbs in pairs?
Yes — bulbs dim with age, so replacing both ensures even light output. A new bulb next to an old one can create uneven illumination.
Related Guides
Alternator vs battery — how to diagnose charging faults and choose the right replacement.
Car Battery Buying GuideCCA ratings, battery group sizes, AGM vs EFB — everything you need to choose the right car battery.
Clock Spring (Airbag Spiral Cable) Buying GuideAirbag warning light, horn failure, and cruise control loss — how a faulty clock spring is diagnosed and what to check before replacement.
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