Mazda 3 Back Up Light Bulb Size

The Mazda 3 back up light requires a 7440 bulb size for this model. The replacement chart covers vehicle production years spanning 2004 to 2009.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
2004-2009	7440

Description	Bulb Size
ANSI standard (US & Canada). Single-filament wedge bulb (T20). 12V, 21W.	7440

The Mazda 3 uses the 7440 bulb size for the back up light across the 2004-2009 model years.
The 7440 is classified under the ANSI standard, which is the designation system used in the United States and Canada for automotive lighting.
This bulb follows the T20 wedge form factor, a designation that refers to its physical shape and base type, where the wedge base replaces a traditional metal contact pin with a plastic wedge that clips directly into the socket.
The 7440 operates on a 12-volt electrical system, which is standard for passenger vehicles of this type.
At 21 watts, the 7440 carries a relatively high wattage for a single-filament wedge bulb, which is typical for reverse light applications that require adequate illumination behind the vehicle.
The single-filament design of the 7440 means it serves one lighting function only, distinguishing it from dual-filament variants in the T20 family, such as the 7443, which would not be a correct fitment for this application.