Compare GMT and JST
See the 9-hour difference between GMT and JST, check overlap hours, and find practical meeting times across the UK and Japan.
How to Find the Time Difference Between GMT and JST
Open the GMT to JST comparison page: Visit
https://www.xconvert.com/time-converter/gmt-vs-jstto load a visual comparison grid with GMT and JST already shown as separate rows across a 24-hour timeline. This page is useful when you are scheduling a call between London-based partners using Greenwich Mean Time and teams in Japan, especially for industries like finance, gaming, manufacturing, and logistics that regularly coordinate with Tokyo.Add other relevant cities with + Add City: Click + Add City and search for cities such as London, Tokyo, Singapore, or New York if you need a broader view of global working overlap. This is practical for multinational teams because Tokyo often works with suppliers across East Asia, while London and New York are common reference points for legal, banking, and trading operations.
Drag on the grid to select a meeting window: Click Select if needed, then drag across the GMT row from 8:00 AM to 10:00 AM GMT to highlight that range in purple; the JST row will show the matching time as 5:00 PM to 7:00 PM JST on the same day because JST is 9 hours ahead of GMT. This makes it easy to confirm that a morning meeting in GMT lands in late afternoon or early evening in Japan, which is often suitable for cross-border client calls but less ideal for long workshops extending past Tokyo business hours.
Export the selected time for your team: After selecting the range, use the export options shown on the page: ICS download, Google Calendar, Gmail, Copy to clipboard, or Share link. For example, a UK operations manager can send the ICS file to a Tokyo procurement team so the event appears in each person’s local calendar automatically, while the share link is useful for remote teams confirming a launch call without manually recalculating the time difference.
GMT vs JST Offset Explained
GMT is UTC+0:00, while JST is UTC+9:00, so JST is 9 hours ahead of GMT year-round. That means when it is 9:00 AM GMT, it is 6:00 PM JST the same calendar day, and when it is 11:00 PM GMT, it is 8:00 AM JST the following day. This next-day rollover matters when booking flights, setting software deployment windows, or arranging customer support handoffs between Europe and Japan.
The key seasonal point is that GMT itself does not observe daylight saving time, and Japan Standard Time also does not observe daylight saving time. Because neither time standard shifts clocks, the difference between GMT and JST stays fixed at 9 hours throughout January, April, July, October, and the rest of the year, with no spring or autumn clock changes to monitor. This makes GMT-to-JST coordination simpler than comparisons involving London local time, because the UK switches to British Summer Time (BST, UTC+1) during part of the year.
That distinction is important in practice: if someone says London time, they may not actually mean GMT in summer. In 2026, for example, the UK is scheduled to move from GMT to BST on 29 March 2026 and return from BST to GMT on 25 October 2026, so during that period Tokyo is 8 hours ahead of London local time, not 9. For contracts, webinars, trading calls, and interview scheduling, using explicit labels like GMT and JST avoids missed meetings caused by confusing GMT with seasonal UK civil time.
Japan’s main business center, Tokyo, has a metropolitan population of roughly 37 million, making it one of the world’s largest urban economies and a major hub for electronics, automotive, shipping, banking, and game publishing. A GMT morning often overlaps with Japan’s late afternoon, which can work well for same-day decision-making between European headquarters and Japanese offices; for example, 7:00 AM GMT = 4:00 PM JST and 10:00 AM GMT = 7:00 PM JST. That overlap is commonly used for supplier calls, investor updates, and coordination between European teams and Japanese manufacturing or regional APAC leadership.
Frequently Asked Questions
What is the exact time difference between GMT and JST?
JST is exactly 9 hours ahead of GMT. If it is 12:00 noon GMT, it is 9:00 PM JST on the same day; if it is 6:00 PM GMT, it is 3:00 AM JST the next day. Because the gap is fixed, it is easier to plan recurring meetings than with time zones that change seasonally.
Does the GMT to JST time difference ever change during the year?
No, the difference between GMT (UTC+0) and JST (UTC+9) remains 9 hours all year. Neither GMT nor Japan Standard Time uses daylight saving time, so there are no clock changes in March, October, or any other month. This consistency is especially useful for long-term vendor agreements, recurring remote standups, and support coverage planning.
Is Tokyo on GMT or JST?
Tokyo uses Japan Standard Time (JST), UTC+9:00, not GMT. Japan has used a single national standard time for decades, and major cities including Tokyo, Osaka, Yokohama, Nagoya, and Fukuoka all follow the same clock. For international scheduling, this means a meeting set for Tokyo applies uniformly across Japan without regional time differences.
When is the best meeting time between GMT and JST?
A practical overlap is usually 7:00 AM to 10:00 AM GMT, which corresponds to 4:00 PM to 7:00 PM JST. This window works well for business calls between Europe and Japan because it falls within normal morning hours in GMT and late business hours in Japan, though meetings after 10:00 AM GMT may push Tokyo participants into evening time. For longer workshops, many teams choose 8:00 AM GMT / 5:00 PM JST as a compromise.
Why do people confuse GMT with London time when comparing with JST?
Many users treat GMT and London time as interchangeable, but they are not always the same. London observes British Summer Time (BST, UTC+1) from late March to late October, while GMT stays at UTC+0 all year; in that summer period, Tokyo is 8 hours ahead of London, but still 9 hours ahead of GMT. This distinction matters for airline bookings, webinar registrations, and calendar invites where one-hour errors can cause missed attendance.
How do I convert 9 AM GMT to JST?
To convert 9:00 AM GMT to JST, add 9 hours, which gives 6:00 PM JST on the same day. This is a common conversion for UK-based teams contacting Japan after their morning start, and it usually lands within standard office hours in Tokyo. The same method works for any GMT time because the offset is fixed and does not change seasonally.
Is GMT or JST better for setting international meeting times?
Neither is universally better, but GMT is often used as a neutral reference in international operations, while JST is essential when the meeting is centered on Japan-based participants or local business hours. For example, a European logistics company coordinating with Tokyo port agents may set the master schedule in GMT, then confirm the local equivalent in JST for warehouse and customs teams. Using both labels in the invite, such as 08:00 GMT / 17:00 JST, reduces ambiguity and helps distributed teams join on time.