GMT to JST Time Converter

When it is 9:00 AM GMT, it is 5:00 PM JST. Japan Standard Time (JST, UTC+9) is 9 hours ahead of Greenwich Mean Time (GMT, UTC+0). There is no full 9–5 overlap between GMT and JST — teams typically rotate early or late meetings.

GMT to JST Conversion Table

Major Cities Using GMT and JST

Greenwich Mean Time (GMT): London, Manchester, Dublin, Edinburgh.

Japan Standard Time (JST): Tokyo, Osaka, Kyoto, Yokohama.

How many hours between GMT and JST?

GMT is UTC+0 and JST is UTC+9, a difference of 9 hours. JST is ahead of GMT. This difference can shift by an hour in either direction during Daylight Saving Time transitions — if one zone observes DST and the other doesn't, the offset narrows or widens for part of the year.

Business Hours Overlap: GMT ↔ JST

Assuming a 9:00 AM – 5:00 PM workday on each side, there is no full 9–5 overlap between gmt and jst — teams typically rotate early or late meetings. To visualize this instantly for any pair of cities, use the visual meeting planner or the timezone overlap finder — both highlight the green overlap window on a live timeline.

Does GMT observe Daylight Saving Time?

Greenwich Mean Time (GMT) is based on the Europe/London IANA timezone. DST observance depends on the jurisdiction — for example, most of the continental US switches between standard and daylight time, while India, Japan, and most of Southeast Asia do not observe DST at all. WorldClock.lol uses the authoritative IANA timezone database, so every conversion automatically accounts for the correct DST rules on the date you're converting.

When is 9 AM GMT in JST?

When it is 9:00 AM in Greenwich Mean Time (GMT, UTC+0), it is 5:00 PM in Japan Standard Time (JST). For other times of day, scan the conversion table above or drop into the interactive converter to pick an exact minute. The converter handles both standard and daylight variants correctly.

How to Use This GMT to JST Converter

1. Type or drag any time in the GMT input above — the JST equivalent updates instantly.
2. Check the day indicator. When the converted time crosses midnight, the tool shows +1 day or −1 day so you don't book a meeting on the wrong date.
3. Copy the shareable URL to send the specific conversion to a colleague — the link preserves your exact selection.
4. Switch directions by swapping the input zones, or open JST to GMT for the reverse.

Related GMT Converters

• GMT to EST
• GMT to PST
• GMT to UTC
• GMT to IST
• GMT to CET
• GMT to AEST

Related JST Converters

• EST to JST
• PST to JST
• UTC to JST
• IST to JST
• CET to JST
• AEST to JST

More Time Tools

• All Time Zone Converters — browse every supported pair
• About GMT (Greenwich Mean Time) — current time, cities, DST rules
• About JST (Japan Standard Time) — current time, cities, DST rules
• Meeting Planner — find the best time for a multi-city meeting
• Best Time to Call — optimal calling windows between any two cities
• UTC Time Now — the reference point for every conversion
• DST Schedule 2026 — every daylight-saving transition this year