GMT to JST Converter – Convert GMT to Japan Time

JST is 9 hours ahead of GMT, so to convert mentally, add 9 hours to your GMT time. For example: 9:00 AM GMT = 6:00 PM JST. Our converter automatically adjusts for Daylight Saving Time so you always get the right result.

JST (Japan Standard Time, UTC+9) is 9 hours ahead of GMT (Greenwich Mean Time, UTC+0) during standard time. For example, 9:00 AM GMT = 6:00 PM JST. During DST periods, this difference changes by 1 hour when one or both zones observe Daylight Saving Time — our converter automatically applies the correct offset for any date you select.

JST is 9 hours ahead of GMT, so standard 9–5 business hours do not overlap. The most practical window is early morning in GMT (7–9 AM), which falls in the evening in JST — for example, 7:00 AM GMT = 4:00 PM JST. Use our meeting planner to find the exact time for your date, especially around DST transitions.

Yes. GMT (Greenwich Mean Time) observes Daylight Saving Time. Clocks spring forward to BST (UTC+1) on the last Sunday in March, and fall back to GMT on the last Sunday in October. During the DST period, the difference with JST changes by 1 hour. In summer the UK switches to BST (British Summer Time, UTC+1). The GMT label itself never changes; it always means UTC+0. Our converter always uses the current offset for the date you select.

Major cities in the GMT (Greenwich Mean Time, UTC+0) timezone include: London (winter), Dublin (winter), Edinburgh, Reykjavik, Accra, Dakar. These cities switch to BST (UTC+1) from the last Sunday in March to the last Sunday in October.

Major cities in the JST (Japan Standard Time, UTC+9) timezone include: Tokyo, Osaka, Yokohama, Nagoya, Sapporo, Kyoto, Fukuoka. JST is a fixed-offset zone — these cities do not observe Daylight Saving Time.

JST is 9 hours ahead of GMT. Because GMT and JST are 9 hours apart, there is no standard business-hour overlap — plan for one side to take an early morning or late evening call. Always include both local times in calendar invites (for example, "2:00 PM GMT / 11:00 PM JST JST"). Double-check around March and November (or March/October for European zones) when DST transitions can shift the offset by 1 hour. For full scheduling guidance, see our international meeting times guide.