BMW X1 Tail Light Bulb Size

The BMW X1 tail light utilizes P21W and 12961 bulb sizes for the rear lighting components. Data for the specified vehicle covers the range from 2016 through 2023.

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
2022-2023	P21W
2020-2021	12961
2016-2019	12961 (With Halogen Capsule Headlamps)

Bulb Specifications

Description	Bulb Size
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W
Philips part number. Miniature wedge bulb (T10) with W2.1x9.5d base. 12V, 5W.	12961

Other Locations

Additional Notes

The BMW X1 tail light specifications cover the 2016-2023 model years, with two distinct bulb types appearing across that range: the P21W for 2022-2023 and the 12961 for 2016-2021.
The P21W is an ECE-standard single-filament signalling bulb rated at 12V and 21W, fitted with a BA15s bayonet base. Its wattage is notably higher than the other bulb type listed in these specifications.
The 12961 is a Philips part number designating a T10 miniature wedge bulb with a W2.1x9.5d base, rated at 12V and 5W. The T10 wedge format is among the most widely used bulb formats in automotive interior and exterior lighting.
The BA15s bayonet base of the P21W and the W2.1x9.5d wedge base of the 12961 are physically incompatible with each other, meaning the two bulb types are not interchangeable despite both operating on a 12V circuit.
For the 2016-2019 BMW X1, the 12961 specification carries a conditional note restricting it to vehicles equipped with Halogen Capsule Headlamps, indicating that headlamp type is a relevant fitment variable for those years.
The 2020-2021 X1 rows list the 12961 without any conditional qualifier, distinguishing them from the 2016-2019 entries where the halogen headlamp condition applies.
The transition from the 12961 to the P21W between the 2021 and 2022 model years represents a change in both base type and wattage, with the P21W drawing significantly more power at 21W compared to the 5W rating of the 12961.