GST to JST Time Converter

When it is 9:00 AM GST, it is 2:00 PM JST. Japan Standard Time (JST, UTC+9) is 5 hours ahead of Gulf Standard Time (GST, UTC+4). Your working-hours overlap window is 9:00 AM–12:00 PM GST (2:00 PM–5:00 PM JST).

GST to JST Conversion Table

Major Cities Using GST and JST

Gulf Standard Time (GST): Dubai, Abu Dhabi, Muscat.

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

How many hours between GST and JST?

GST is UTC+4 and JST is UTC+9, a difference of 5 hours. JST is ahead of GST. 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: GST ↔ JST

Assuming a 9:00 AM – 5:00 PM workday on each side, your working-hours overlap window is 9:00 am–12:00 pm gst (2:00 pm–5:00 pm jst). 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 GST observe Daylight Saving Time?

Gulf Standard Time (GST) is based on the Asia/Dubai 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 GST in JST?

When it is 9:00 AM in Gulf Standard Time (GST, UTC+4), it is 2:00 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 GST to JST Converter

1. Type or drag any time in the GST 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 GST for the reverse.

Related GST Converters

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

Related JST Converters

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

More Time Tools

• All Time Zone Converters — browse every supported pair
• About GST (Gulf Standard 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