Ford Focus brake bulb sizes include 3157 and 3057, while the center high mount stop light uses a 12961 bulb size. The replacement chart contains vehicle production years and bulb size specifications spanning 2008 to 2018.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Ford Focus uses the 3157 bulb for the brake light across the 2012-2018 model years, as well as the 2008-2009 model years.
The 3157 is an ANSI-standardized dual-filament wedge bulb in the T25 form factor, rated at 12V with a 27W high filament and a 7W low filament, making it suitable for combined stop and tail light functions.
The 2010-2011 Ford Focus brake light position uses the 3057 bulb instead of the 3157.
The 3057 shares the same ANSI classification, T25 form factor, and 12V/27W/7W electrical ratings as the 3157, meaning the two bulbs are electrically equivalent in output.
Despite their electrical equivalence, the 3057 and 3157 are not unconditionally interchangeable in all sockets, as differences in base construction between the two types can affect fitment depending on the socket design used in a given vehicle.
The center high mount stop light (CHMSL) on the 2008-2011 Ford Focus takes the 12961 bulb, a specification that differs from the standard brake light position on the same vehicles.
The 12961 is a Philips part number designation for a miniature wedge bulb in the T10 form factor, using a W2.1x9.5d base and rated at 12V, 5W, which is a single-filament configuration suited to a dedicated stop light role.
The W2.1x9.5d base on the 12961 is a metric wedge base type, and bulbs carrying different base designations are not physically compatible with sockets designed for this specification.