What's the difference between Dual Beam and Single Beam headlight bulbs?

On Oct 18, 2020

“Do I have dual-beam or single-beam headlight bulbs?” The answer to the issue often brings confusion, but it is surprisingly simple:

The term “Dual” and “Single” refer the function of a headlight bulb. A dual-beam headlight bulb has dual functions; The bulb creates a low along with a high beam – “dual beams” in a single headlight bulb. A single-beam headlight bulb has a single function; the main one bulb creates only one beam (either low or high beam individually).

HOW To recognize DUAL BEAM BULBS:

Dual Beam Headlight Bulbs have dual filaments which produce dual beam patterns: one bulb creates both high and low beam.

Since a dual beam headlight bulb can create dual beam patterns, only one bulb is needed per headlight housing. That one dual beam headlight bulb can create the high beam and the low beam.

HOW To recognize SINGLE BEAM BULBS:

Single Beam Headlight Bulbs get one single filament inside the bulb which produces a single beam pattern: either high beam or low beam.

Since just one beam headlight bulb can only create a single beam pattern, one bulb is needed for a high beam bulb and a second bulb is needed for any low beam bulb.

Just remember if you’re taking a look at an LED headlight bulb or HID conversion kit and you’re unclear about the difference, just remember to focus on the bulbs themselves, not the headlight housing. Have you got a bulb that does 2 beams in 1 bulb or 1 beam in 1 bulb?