How do I know what bulb fits my car?
Identify the exact bulb your car needs by checking the owner’s manual, reading the markings on the current bulb, and using a reputable fitment tool that matches your car’s year, make, and model to confirm the correct bulb base (for example H11, 9005, or H4). If you’re unsure, bring the old bulb to a parts store or consult their online charts.
Quick checks to identify the exact bulb type
This set of checks helps you confirm the bulb base and rating without trial and error.
- Check the owner’s manual for the exact bulb type (for example H11, 9005, or H4).
- Remove the bulb from the socket or inspect the existing bulb and read any markings on the base or glass (the code is usually printed on the base).
- Look for a label on the headlamp housing or inside the service manual that lists the bulb part number for your model.
- Use a vehicle-fitment tool from a trusted retailer: enter your car’s year, make, and model to confirm compatible bulb types.
- Compare the bulb’s base shape and connector to the replacement you’re considering to avoid a mismatch.
With these checks, you’ll narrow the options to the correct base type and avoid buying the wrong bulb.
In-vehicle verification: confirm in person
Follow these steps to physically confirm the exact bulb you need, and to install safely.
- Ensure the vehicle is off, parking brake applied, and headlights off. Open the hood and locate the headlight assembly.
- Disconnect the electrical connector from the bulb and remove any retaining clip or cap required to release the bulb.
- Carefully remove the bulb and inspect the base for markings; note the base type and wattage if printed.
- Match those markings to a replacement bulb, or use the retailer’s fitment tool with your car’s year/make/model for final confirmation.
- Handle bulbs with gloves or a clean tissue; avoid touching the glass of halogen bulbs to prevent oils from shortening life.
- Reinstall, reconnect the wiring, and test the lights to ensure proper operation and alignment.
If you cannot read markings or the label is missing, photograph the bulb and consult a professional or use a retailer’s cross-reference with your vehicle details.
Bulb types and compatibility
Halogen basics
Most cars still rely on halogen bulbs. They come in common base types such as H1, H4, H7, and H11, with wattages typically around 55-60W. The base shape determines fit and the housing’s reflector; always verify wattage and beam pattern in the owner’s manual or on the bulb’s packaging to ensure compatibility with your headlight assembly.
LED and HID considerations
LED and HID replacements can offer brighter, whiter light, but they require proper compatibility with the vehicle’s electrical system and headlight housing. LED bulbs must match the base type and often need CANBUS resistors to avoid flicker or warning codes. HID kits require a ballast and a housing designed for HID; using halogen-style bulbs in an HID setup or vice versa can cause performance or safety issues. Always choose bulbs that your vehicle manufacturer explicitly supports.
Wiring and safety notes
Some vehicles use specialized bulbs with integrated ballasts or nonstandard connectors. If in doubt, consult a professional or use a known-compatible bulb recommended by the manufacturer or a reputable retailer.
Tools, resources, and tips
These resources help you verify compatibility before purchase and avoid common pitfalls.
- Owner’s manual or the vehicle manufacturer’s website for your specific bulb type.
- Current bulb markings: base type (like H11, 9005) and wattage if printed.
- Retailer fitment tools: online lookup pages where you enter year, make, model, and sometimes trim.
- Cross-reference charts from bulb manufacturers (Philips, Sylvania/Osram) and reliable automotive guides.
- VIN-based search or dealership service portals if available.
Using these tools reduces the chance of buying an incompatible bulb and ensures compliant operation with your vehicle’s lighting system.
Summary
To know what bulb fits your car, start with the owner’s manual, then read any markings on the current bulb, and use trusted fitment tools that match your vehicle’s year, make, and model. If you’re unsure, seek help from a parts store or a professional who can verify compatibility before you buy or install. Always handle bulbs carefully, especially halogen bulbs, to avoid skin oils and ensure safe installation.
How do I figure out what size bulb I need?
The numbers of the bulb indicate its size, which is based on its diameter at its widest point, measured in eighths of an inch (⅛”). For example: An A19 bulb indicates that the bulb comes in a standard household shape (code A), and the '19' indicates that the bulb is 19/8ths inches in size.
How do I tell which bulb I need?
When you're replacing your light bulbs, you also need to think about which bulb shape you need. Some bulbs will need a like for like replacement, such as a spotlight shaped bulb. You should also consider the style of your light fixture and whether a different bulb shape will suit it.
How do I find out what bulbs my car takes?
You can also look in your vehicle handbook in the lighting section of the manual. If you don't have your registration number or vehicle handbook, you can identify the replacement bulb you need by removing the old one. You should be able to see the bulb's application number, which might begin with a D, H or P.
How do I know what light bulb I need for my car?
For a bulb installed in your car, you can find the number stamped or printed on the side of the bulb. It's also listed in the service manual and in an auto bulb guide. Only the correct bulb size will fit in the headlamp housing and connect to the factory wiring.
