Kia Optima License Plate Bulb Size

The Kia Optima license plate light uses 12961 and 168 bulb sizes for the exterior illumination of the rear registration area. Data for the specific components covers the range from 2001 through 2020.

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
2019-2020	12961
2017-2018	168
2001-2013	168

Bulb Specifications

Description	Bulb Size
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12961
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 4.9W.	168

Other Locations

Additional Notes

The 168 bulb is the most frequently specified license plate bulb across the Kia Optima lineup, covering model years 2001-2018 with the exception of 2019 and 2020, and also excluding 2014-2016.
The 168 is an ANSI-standardized miniature wedge bulb rated at 12V and 4.9W, with the T10 wedge form factor being the defining physical characteristic shared across both bulb types in these specifications.
The 12961 is a Philips-designated part number rather than an ANSI standard designation, and it applies to the Kia Optima for the 2019-2020 model years.
The 12961 carries a W2.1x9.5d base classification, which is the formal IEC designation for the T10 wedge base type, specifying a 2.1mm wire width and a 9.5mm wedge depth.
Both the 168 and the 12961 share the T10 wedge form factor, though their wattage ratings differ slightly: the 168 is rated at 4.9W while the 12961 is rated at 5W.
Despite the physical similarity between the two bulb types, the 168 and 12961 are listed under separate model year groups for the Kia Optima, indicating that direct interchangeability is not confirmed by these specifications.
The 12961 operates at 12V, which matches the 12V rating of the 168, meaning both bulbs are compatible with standard automotive electrical systems in terms of voltage.
The T10 wedge base requires no locking mechanism for installation, as the wedge shape itself provides retention within the socket, a characteristic common to both bulb types listed here.