Time Difference: London and Tokyo
Tokyo is 9 hours ahead of London in winter and 8 hours ahead in summer. 8:00 AM in London is 5:00 PM in Tokyo on GMT and 4:00 PM on BST.
Daylight saving note: Tokyo never changes its clocks. It is 9 hours ahead of London on GMT and 8 hours ahead on BST, which runs from the last Sunday in March to the last Sunday in October.
London and Tokyo Hardly Share a Workday
London is UTC+0 in winter and UTC+1 in summer, and Tokyo is UTC+9 all year. The gap is 9 hours on GMT and 8 hours on BST. London's clock change is the only moving part.
Add 9 in winter and 8 in summer. 7:00 AM in London is 4:00 PM in Tokyo on GMT and 3:00 PM on BST, so London's early morning is Tokyo's late afternoon.
Going the other way, Tokyo's 9:00 AM is 12:00 AM in London on GMT and 1:00 AM on BST, which is the middle of the London night.
London to Tokyo Conversion Table
Each column is one real season of the London-Tokyo gap. Pick the column that matches your date.
| 🇬🇧 London (GMT) | 🇯🇵 Tokyo (GMT → JST) | 🇯🇵 Tokyo (BST → JST) |
|---|---|---|
| 00:00 | 09:00 | 08:00 |
| 03:00 | 12:00 | 11:00 |
| 06:00 | 15:00 | 14:00 |
| 09:00 | 18:00 | 17:00 |
| 12:00 | 21:00 | 20:00 |
| 15:00 | 00:00(next day) | 23:00 |
| 18:00 | 03:00(next day) | 02:00(next day) |
| 21:00 | 06:00(next day) | 05:00(next day) |
- GMT → JST: last Sunday in October to last Sunday in March, while the UK is on GMT
- BST → JST: last Sunday in March to last Sunday in October, while the UK is on BST
* "next day" / "prev day" = the converted time falls on a different calendar date.
The Narrow London-Tokyo Window
On 9-to-5 days, the overlap is zero in winter and one hour in summer. London's 9:00 AM is Tokyo's 6:00 PM in winter, after the Tokyo close. On BST, 8:00 to 9:00 AM in London is 4:00 PM to 5:00 PM in Tokyo. In winter, 7:00 to 8:00 AM in London is 4:00 PM to 5:00 PM in Tokyo.
Avoiding London-Tokyo Time Mistakes
Tokyo is ahead, so a late evening in London is already the next calendar day in Tokyo. With a 9 hours gap, that starts at 3:00 PM in London: 3:30 PM there is 12:30 AM the next day in Tokyo. When the gap narrows to 8 hours, the date line moves to 4:00 PM.
Tokyo doesn't change, so a Tokyo-hosted series drifts on London's clock. 4:00 PM in Tokyo is 7:00 AM in London in winter and 8:00 AM in summer. Add both times to the invite and check the weeks around each UK clock change.
A Worked Example: A Quarterly Review Between London and Tokyo
Say a London team and a Tokyo team hold a short review that has to fit between London's early morning and Tokyo's late afternoon. A 7:30 AM London start is 4:30 PM in Tokyo on GMT and 3:30 PM on BST. A 30 minute call from 8:00 AM London time ends at 4:30 PM Tokyo time on BST.
If Tokyo hosts, the cost lands on London. A 5:00 PM Tokyo start is 8:00 AM in London on GMT and 9:00 AM on BST. A 4:00 PM Tokyo start is 7:00 AM in winter, which is before most London offices open.
Because Tokyo never changes, the Tokyo time of a London-hosted call moves by an hour in March and October, and the London time of a Tokyo-hosted call moves the same way. Put both in the title, such as "Review, 8:00 AM London / 4:00 PM Tokyo".
Frequently Asked Questions
What is the time difference between London and Tokyo?
Tokyo is 9 hours ahead of London while the UK is on GMT and 8 hours ahead while it is on BST. Tokyo doesn't change its clocks.
What time is 9 AM in London in Tokyo?
On GMT, 9:00 AM in London is 6:00 PM in Tokyo. On BST it's 5:00 PM. Either way it's the same evening.
When does the London-Tokyo gap change?
On the last Sunday in March, when the UK moves to BST and the gap narrows from 9 hours to 8, and on the last Sunday in October, when it widens back. Tokyo has no change.
What is the best time for a London-Tokyo call?
London early morning. In summer, 8:00 to 9:00 AM is 4:00 PM to 5:00 PM in Tokyo. In winter, 7:00 to 8:00 AM is 4:00 PM to 5:00 PM.