JST to GMT Converter – Convert Japan Time to GMT

GMT is 9 hours behind JST, so to convert mentally, subtract 9 hours to your JST time. For example: 9:00 AM JST = 12:00 AM GMT. Our converter automatically adjusts for Daylight Saving Time so you always get the right result.

GMT (Greenwich Mean Time, UTC+0) is 9 hours behind JST (Japan Standard Time, UTC+9) during standard time. For example, 9:00 AM JST = 12:00 AM GMT. 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 behind GMT, so standard 9–5 business hours do not overlap. The most practical window is late afternoon in JST (5–7 PM), which falls in the morning in GMT — for example, 5:00 PM JST = 8:00 AM GMT. Use our meeting planner to find the exact time for your date, especially around DST transitions.

Japan does not observe Daylight Saving Time. JST remains constant year-round, which simplifies conversions.

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.

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.

GMT is 9 hours behind JST. Because JST and GMT 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 JST / 5:00 AM GMT GMT"). 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.