What Is JST?
JST stands for Japan Standard Time, a timezone at UTC+09:00 (9 hours ahead of Coordinated Universal Time) from Coordinated Universal Time. It is used in Japan (all 47 prefectures). The IANA Time Zone Database, the authoritative global reference used by operating systems, programming languages, and web services, records this zone under the identifier Asia/Tokyo. IANA identifiers are unambiguous: Asia/Tokyo maps to exactly one timezone in the world, unlike the abbreviation JST, which is specific to this region. JST does not observe Daylight Saving Time: the UTC+09:00 offset is fixed year-round.
Japan Standard Time is based on the 135th meridian east longitude (135°E), which passes through Akashi, Hyogo Prefecture. The official timekeeping authority is the National Institute of Information and Communications Technology (NICT) in Tokyo.
Current JST Time and Date
The clock above shows the current JST time: 19:47 on Friday, March 6, 2026. It is calculated using the browser's Intl.DateTimeFormat API with the IANA identifier Asia/Tokyo, the same source your phone and laptop use for timezone conversions. The time updates every second. If you need a static reference, note that JST is always UTC+09:00 from UTC : it never observes Daylight Saving Time.
JST to UTC Conversion
To convert JST to UTC: subtract 09:00 from the JST time. Example: 14:00 JST = 05:00 UTC. In ISO 8601 format, a JST timestamp is written as 2026-03-06T19:47:00+09:00. This format is unambiguous and machine-readable, always prefer it over abbreviation-only notation for data exchange.
Cities in the JST Timezone
Major cities that observe JST (UTC+09:00) include:
These cities all share the IANA zone identifier Asia/Tokyo (or a zone with the same current offset). Click any city link to see its live clock, DST status, and time difference from major world cities.
DST Transition Dates for JST
Japan Standard Time does not observe Daylight Saving Time. The offset is fixed at UTC+09:00 year-round. This makes JST one of the most predictable timezones for international scheduling, the offset you see today is the offset you will see in six months.
DST Variants: JST vs Standard Time
JST does not observe Daylight Saving Time. The UTC+09:00 offset applies every day of the year, no seasonal adjustment, no clock changes.
Why Timezone Abbreviations Are Ambiguous
ISO 8601, the international standard for date and time notation, does not define timezone abbreviations. IANA, which maintains the authoritative timezone database, uses geographic identifiers (America/New_York, Asia/Kolkata) rather than abbreviations. Abbreviations emerged from railway timetables and military communications in the 19th and early 20th centuries, before any international standardization effort.
The result is a patchwork. EST is used in North America for UTC-05:00 and in parts of Australia for UTC+10:00 or UTC+11:00. IST covers three different UTC offsets across three continents. CST applies to UTC-06:00 (US Central), UTC+08:00 (China), and UTC-05:00 (Cuba). Even GMT, seemingly the anchor, is used differently than UTC: GMT is a timezone designation specific to the UK and West Africa, while UTC is the mathematical standard maintained by atomic clocks. They share the same offset (UTC+00:00) but are not interchangeable in formal contexts.
Best practice: always write the numeric offset alongside the abbreviation (JST (UTC+09:00)) or use ISO 8601 format for machine-readable timestamps. For the IANA identifier, use Asia/Tokyo.
Converting JST to Major World Timezones
Current conversions from JST (19:47) to other major timezones:
- New York (EST/EDT): 05:47 (UTC-05:00)
- London (GMT/BST): 10:47 (UTC+00:00)
- Dubai (GST): 14:47 (UTC+04:00)
- India (IST): 16:17 (UTC+05:30)
- Singapore (SGT): 18:47 (UTC+08:00)
- Sydney (AEST/AEDT): 21:47 (UTC+11:00)