JST
Japan Standard Time
GMT +9
GMT/BST
Greenwich Mean Time
GMT +0
BST automatically adjusted to GMT time zone, that is in use

Time Difference

Japan Standard Time is 9 hours ahead of Greenwich Mean Time
9:00 pm21:00 in JST is 12:00 pm12:00 in GMT

JST to BST call time
Best time for a conference call or a meeting is between 4pm-6pm in JST which corresponds to 8am-10am in BST

9:00 pm21:00 Japan Standard Time (JST). Offset UTC +9:00 hours
12:00 pm12:00 Greenwich Mean Time (GMT). Offset UTC 0:00 hours

9:00 pm21:00 JST / 12:00 pm12:00 GMT

JST GMT
12am (midnight) 3pm
1am 4pm
2am 5pm
3am 6pm
4am 7pm
5am 8pm
6am 9pm
7am 10pm
8am 11pm
9am 12am (midnight)
10am 1am
11am 2am
12pm (noon) 3am
1pm 4am
2pm 5am
3pm 6am
4pm 7am
5pm 8am
6pm 9am
7pm 10am
8pm 11am
9pm 12pm (noon)
10pm 1pm
11pm 2pm
0:00 15:00
1:00 16:00
2:00 17:00
3:00 18:00
4:00 19:00
5:00 20:00
6:00 21:00
7:00 22:00
8:00 23:00
9:00 0:00
10:00 1:00
11:00 2:00
12:00 3:00
13:00 4:00
14:00 5:00
15:00 6:00
16:00 7:00
17:00 8:00
18:00 9:00
19:00 10:00
20:00 11:00
21:00 12:00
22:00 13:00
23:00 14:00

Japan Standard Time

Offset: JST is 9 hours ahead Greenwich Mean Time (GMT) and is used in Asia

Countries: It is used in following countries: Japan

Principal Cities: The largest city in the JST timezone is Tokyo from Japan with population about 8.337 million people. Other major cities in the area are Yokohama, Osaka shi, Nagoya shi, Sapporo

Daylight Saving: Japan Standard Time (JST) is not adjusted for daylight saving therefore JST remains the same through out the year. This means, unlike some time zones where the clock is set forward by one hour every summer and backward by one hour during winter to adjust for daylight saving, Japan Standard Time remains the same

JST Time Zone Geo Map
JST timezone map

JST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • +09 - basic short
  • +0900 - basic
  • +09:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0900 - sign character (+) followed by a four digit time providing hours (09) and minutes (00) of the offset. Indicates nine hour and zero minutes time differences to the east of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • India - Military abbreviation for JST
  • I - short form of 'India'
IANA/Olson: Reflects JST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Asia/Tokyo
  • Japan
Time zones with the GMT +9 offset:
  • AWDT - Australian Western Daylight Time
  • CHOST - Choibalsan Summer Time
  • I - India Time Zone
  • IRKST - Irkutsk Summer Time
  • JST - Japan Standard Time
  • KST - Korea Standard Time
  • PWT - Palau Time
  • TLT - East Timor Time
  • ULAST - Ulaanbaatar Summer Time
  • WIT - Eastern Indonesian Time
  • YAKT - Yakutsk Time

British Summer Time

Offset: BST is 1 hour ahead Greenwich Mean Time (GMT) and is used in Europe

Countries: It is used in following countries: Britain (UK), Guernsey, Isle of Man, Jersey

Principal Cities: The largest city in the BST timezone is London from United Kingdom with population about 7.557 million people. Other major cities in the area are Birmingham, Glasgow, Liverpool, Saint Helier

Greenwich Mean Time (GMT) originally referred to the mean solar time at the Royal Observatory in Greenwich, London. It is now often used to refer to Coordinated Universal Time (UTC) when this is viewed as a time zone, and in casual use for the most parts it is the same. In military GMT is known as Zulu time.Greenwich Mean Time was the same as Universal Time (UT), until the introduction of UTC in 1972 a standard astronomical concept used in many technical fields.

BST Time Zone Geo Map
BST timezone map

BST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • +01 - basic short
  • +0100 - basic
  • +01:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0100 - sign character (+) followed by a four digit time providing hours (01) and minutes (00) of the offset. Indicates one hour and zero minutes time differences to the east of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Alpha - Military abbreviation for BST
  • A - short form of 'Alpha'
IANA/Olson: Reflects BST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Europe/Belfast
  • Europe/Guernsey
  • Europe/Isle_of_Man
  • Europe/Jersey
  • Europe/London
  • GB
  • GB-Eire
BST Abbreviation: Several time zones share BST abbreviation and it could refer to these time zones
  • British Summer Time - UTC +1
  • Bangladesh Standard Time - UTC +6
  • Bougainville Standard Time - UTC +11
  • Brasilia Standard Time - UTC -3
Time zones with the GMT +1 offset:
  • BST - British Summer Time
  • CET - Central European Time
  • IST - Irish Standard Time
  • WEST - Western European Summer Time
  • A - Alpha Time Zone
  • CET - Central European Time
  • MEZ - Mitteleuropäische Zeit
  • WAT - West Africa Time
  • WST - Western Sahara Summer Time
  • BMT - Biel Mean Time