JSTtoGMTJapan Standard Time to Greenwich Mean Time
JST
Japan Standard Time (GMT+9)GMT
Greenwich Mean Time (GMT)Feasible Shoulder Hours Window
Recommended calling window between JST and GMT
There are no overlapping 9-to-5 working hours between JST and GMT. The optimal compromise window falls during morning/evening shoulder periods (7:00 AM – 9:00 PM) when participants in both locations are awake.
24-Hour Schedule Conversion Matrix
Compare every hour of the day between JST and GMT.
| JST Time (Japan Standard Time) | GMT Time (Greenwich Mean Time) | Status & Recommendation |
|---|---|---|
| 00:00AM | 15:00PM-1 day | ⚪ Outside Work Hours |
| 01:00AM | 16:00PM-1 day | ⚪ Outside Work Hours |
| 02:00AM | 17:00PM-1 day | ⚪ Outside Work Hours |
| 03:00AM | 18:00PM-1 day | ⚪ Outside Work Hours |
| 04:00AM | 19:00PM-1 day | ⚪ Outside Work Hours |
| 05:00AM | 20:00PM-1 day | ⚪ Outside Work Hours |
| 06:00AM | 21:00PM-1 day | ⚪ Outside Work Hours |
| 07:00AM | 22:00PM-1 day | ⚪ Outside Work Hours |
| 08:00AM | 23:00PM-1 day | ⚪ Outside Work Hours |
| 09:00AM | 00:00AM | ⚪ Outside Work Hours |
| 10:00AM | 01:00AM | ⚪ Outside Work Hours |
| 11:00AM | 02:00AM | ⚪ Outside Work Hours |
| 12:00PM | 03:00AM | ⚪ Outside Work Hours |
| 13:00PM | 04:00AM | ⚪ Outside Work Hours |
| 14:00PM | 05:00AM | ⚪ Outside Work Hours |
| 15:00PM | 06:00AM | ⚪ Outside Work Hours |
| 16:00PM | 07:00AM | 🟡 Feasible (Shoulder Hour) |
| 17:00PM | 08:00AM | ⚪ Outside Work Hours |
| 18:00PM | 09:00AM | ⚪ Outside Work Hours |
| 19:00PM | 10:00AM | ⚪ Outside Work Hours |
| 20:00PM | 11:00AM | ⚪ Outside Work Hours |
| 21:00PM | 12:00PM | ⚪ Outside Work Hours |
| 22:00PM | 13:00PM | ⚪ Outside Work Hours |
| 23:00PM | 14:00PM | ⚪ Outside Work Hours |
Frequently Asked Questions
What is the time difference between JST and GMT?
GMT is 9 hours behind JST. When it is 12:00 PM (noon) in JST, the current synchronized time in GMT is 3:00 AM.
What are the overlapping working hours between JST and GMT?
Due to the timezone separation, standard 9-to-5 working shifts do not overlap. The recommended compromise window falls during morning/evening shoulder periods (4:00 PM – 9:00 PM in JST = 7:00 AM – 12:00 PM in GMT).
Does daylight saving time affect the conversion between JST and GMT?
Yes. GMT observes daylight saving shifts (BST), shifting the offset difference by 1 hour between summer and winter while JST stays on fixed standard time year-round.
What regions and major cities observe JST and GMT?
JST (Japan Standard Time) is primarily observed across East Asia (Japan) (key hubs include Tokyo, Osaka, Yokohama, Nagoya). GMT (Greenwich Mean Time) is observed across Western Europe & West Africa (United Kingdom, Ireland, Portugal, Ghana) (key hubs include London, Dublin, Lisbon, Accra).
What is 9:00 AM JST in GMT?
9:00 AM in JST corresponds to 12:00 AM in GMT. You can cross-reference every hour of the day in the 24-hour visual schedule table above.
Which time zone is ahead, JST or GMT?
JST is ahead by 9 hours.