Subaru Legacy Turn Signal Bulb Size

Subaru Legacy front turn signal bulbs use 1157, 7444NA, or 7440NA sizes, while rear turn signal bulbs use 921, 1157, or 7440NA sizes. The replacement bulb chart covers 1990 to 2024 model years with corresponding specifications.

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

Front Turn Signal

If US Type and EU Type show the same value, a direct cross-reference for this bulb is not available or the data is insufficient.

Years	US Type	EU Type	Shop
2023-2024	1157	P21/5W	Check Price
2019-2022	7444NA	WY21/5W	Check Price
2013-2018	7440NA	WY21W	Check Price
2010-2012	7440	W21W	Check Price
2008-2009	3457NA	PY27/7W	Check Price
1998-1999	1157	P21/5W	Check Price
1997	1034NA	1034NA	Check Price
1995-1996	1157NA	P21/5W	Check Price
1994	1034NA	1034NA	Check Price
1993	1157NA	P21/5W	Check Price
1992	1034NA	1034NA	Check Price
1990-1991	921	W16W	Check Price

Rear Turn Signal

Years	US Type	EU Type	Shop
2024	921	W16W	Check Price
2023	1157	P21/5W	Check Price
2008-2022	7440NA	WY21W	Check Price
1990-1999	1156	P21W	Check Price

Bulb Specifications

Description	Type	Shop
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base. 12V, 21W/5W.	1157	Check Price
ECE standard (Europe & worldwide). Dual-filament signalling bulb with BAY15d bayonet base. 12V, 21W/5W.	P21/5W	Check Price
ANSI standard (US & Canada). Dual-filament wedge bulb (T20), natural amber glass. 12V, 21W/5W.	7444NA	Check Price
ANSI standard (US & Canada). Single-filament wedge bulb (T20), natural amber glass. 12V, 21W.	7440NA	Check Price
ANSI standard (US & Canada). Single-filament wedge bulb (T20). 12V, 21W.	7440	Check Price
ANSI standard (US & Canada). Dual-filament wedge bulb (T25), natural amber glass. 12V, 27W/7W.	3457NA	Check Price
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base, natural amber glass. Variant of 1157. 12V, 21/5W.	1034NA	Check Price
ANSI standard (US & Canada). Dual-filament bulb with BAY15d bayonet base, natural amber glass. 12V, 21W/5W.	1157NA	Check Price
ANSI standard (US & Canada). Wedge bulb (T15). 12V, 16W.	921	Check Price
ANSI standard (US & Canada). Single-filament bulb with BA15s bayonet base. 12V, 21W.	1156	Check Price
ECE standard (Europe & worldwide). Single-filament signalling bulb with BA15s bayonet base. 12V, 21W.	P21W	Check Price

Other Locations

Additional Notes

The 7440NA bulb is the most frequently specified type across the Subaru Legacy turn signal positions. It is a single-filament T20 wedge bulb rated at 12V and 21W, constructed with natural amber glass, which produces the amber signal color without relying on a tinted lens or housing.
The "NA" suffix found on several bulb types in these specifications, including the 7440NA, 7444NA, 3457NA, 1034NA, and 1157NA, denotes natural amber glass. This construction filters the light output to amber at the source rather than through an external lens, a design approach associated with SAE and ECE signaling standards.
The 7444NA, used in the Subaru Legacy front turn signal for 2019-2022, shares the same T20 wedge base as the 7440NA but carries a dual-filament design rated at 21W/5W. The two bulbs are not interchangeable despite their physical similarities, as the 7444NA accommodates a secondary low-wattage filament that the 7440NA does not.
The 1157 and its variants, the 1157NA and 1034NA, all use a BAY15d bayonet base with a dual-filament configuration rated at 12V and 21W/5W. The BAY15d base features two offset pins at different heights, which prevents incorrect insertion and distinguishes it from single-filament bayonet bases.
The 2024 Legacy front turn signal specifies a 1157, while the 2024 rear turn signal specifies a 921. These two bulbs use different base types and wattage ratings and are not interchangeable between positions.
The 921 is a T15 wedge bulb rated at 12V and 16W with a single filament. It carries a lower wattage than the 7440 and 7440NA T20 wedge bulbs and occupies a physically smaller housing, making cross-substitution between these wedge types incompatible despite their shared wedge-style base format.
The 1156, specified for the Legacy rear turn signal from 1990-1999, uses a BA15s single-contact bayonet base rated at 12V and 21W. The BA15s base differs from the BAY15d base used by the 1157 family in that it has a single pin and no offset, making the two base types mechanically incompatible.
The 3457NA, specified for the 2008-2009 Legacy front turn signal, is a dual-filament T25 wedge bulb rated at 12V and 27W/7W. Its higher wattage output and larger T25 body distinguish it from the T20-based 7440NA and 7444NA bulbs used in adjacent model years, and the two types are not interchangeable.