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.
Do London and Tokyo Share a Working Day?
If both teams keep strict 9-to-5 hours, there's no overlap in either season. London's 9:00 AM is 6:00 PM in Tokyo on GMT and 5:00 PM on BST, which is Tokyo's closing time or later. The table below shows each London hour next to its Tokyo time.
| London | Tokyo (GMT → JST) | Tokyo (BST → JST) |
|---|---|---|
| 8:00 AM | 5:00 PM | 4:00 PM |
| 9:00 AM | 6:00 PM | 5:00 PM |
| 10:00 AM | 7:00 PM | 6:00 PM |
| 11:00 AM | 8:00 PM | 7:00 PM |
| 12:00 PM | 9:00 PM | 8:00 PM |
| 1:00 PM | 10:00 PM | 9:00 PM |
| 2:00 PM | 11:00 PM | 10:00 PM |
| 3:00 PM | 12:00 AM (next day) | 11:00 PM |
| 4:00 PM | 1:00 AM (next day) | 12:00 AM (next day) |
| 5:00 PM | 2:00 AM (next day) | 1:00 AM (next day) |
| 6:00 PM | 3:00 AM (next day) | 2:00 AM (next day) |
Each row is an hour of the London day. A check mark means both cities are inside a 9 AM to 5 PM working day at that moment.
- GMT → JST: no shared working hours.
- BST → JST: no shared working hours.
A slot only exists if London starts early. In summer, 8:00 to 9:00 AM London time is 4:00 PM to 5:00 PM in Tokyo. In winter, 7:00 to 8:00 AM London time is 4:00 PM to 5:00 PM in Tokyo.
Tokyo Stays Put, London Moves
London is UTC+0 in winter and UTC+1 in summer, and Tokyo is UTC+9 all year, so the gap is 9 hours on GMT and 8 on BST. Tokyo never changes its clocks. BST runs from the last Sunday in March to the last Sunday in October, and that 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. That's the middle of the London night, so a time that suits Tokyo's morning costs London a very late or very early hour.
London to Tokyo Conversions by Season
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.
Recurring Calls Drift
A series fixed in Tokyo time drifts on London's clock. 4:00 PM in Tokyo is 7:00 AM in London in winter and 8:00 AM in summer. Put both times in the invite and check the weeks around each UK clock change, when the London time moves by an hour.
Fitting a Short Review Between the Two Cities
Picture 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".