GMT to JST Time Converter - Live World Clock

Convert time between Greenwich Mean Time (GMT) and Japan Standard Time (JST). See current time with live clocks.

United Kingdom (GMT)

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06:27:46 PM
Thursday, August 20, 2026

Japan (JST)

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02:27:46 AM
Friday, August 21, 2026

Current Time Difference

GMT is -9 hours behind JST

What is GMT (Greenwich Mean Time)?

Greenwich Mean Time (GMT) is the reference point for world time zones, UTC+0:00.

Countries and Regions Using GMT

Primary Country:

  • United Kingdom

Also Used By:

  • Ireland
  • Portugal

Key Facts about GMT:

  • ✓ Prime meridian reference point
  • ✓ London financial center
  • ✓ Historical timekeeping standard
  • ✓ Major Cities: London, Manchester, Birmingham, Leeds, Glasgow
  • ✓ UTC Offset: +0:00 (+1:00 during BST)

What is JST (Japan Standard Time)?

Japan Standard Time (JST) used in Japan, UTC+9:00.

Countries and Regions Using JST

Primary Country:

  • Japan

Also Used By:

  • South Korea

Key Facts about JST:

  • ✓ Third largest economy
  • ✓ Major tech center
  • ✓ No DST observed
  • ✓ Major Cities: Tokyo, Osaka, Yokohama, Nagoya
  • ✓ UTC Offset: +9:00

GMT to JST Time Difference

Standard Time Difference:

GMT is -9 hours behind

Common Use Cases:

  • • Business meetings between United Kingdom and Japan
  • • International collaboration across timezones
  • • Scheduling calls and conferences

Frequently Asked Questions

Which countries are in GMT time zone?

United Kingdom is the primary country using GMT (+0:00). Other countries include: Ireland, Portugal.

Which countries are in JST time zone?

Japan is the primary country using JST (+9:00). Other countries include: South Korea.

How many hours is GMT ahead of JST?

GMT is -9 hours behind JST.

Does United Kingdom observe Daylight Saving Time?

Yes, United Kingdom observes Daylight Saving Time. During DST, GMT changes to BST (British Summer Time) with UTC offset of +1:00.