The short answer

12am in Greenwich Mean Time is 8am in Japan Standard Time.

Greenwich Mean Time is 8 hours behind Japan Standard Time. That's early morning in Japan Standard Time, before the typical working day begins.

Greenwich Mean Time
12am
Japan Standard Time
8am
Right now
7:43amBST · UTC+01:00 · Mon, Jun 22
3:43pmJST · UTC+09:00 · Mon, Jun 22
Read across to convert
Greenwich Mean Time
BST · UTC+01:00
7:43am ☀
Japan Standard Time
JST · UTC+09:00
3:43pm ☀
Pinned12amGreenwich Mean Time=8amJapan Standard Time
PINNED
12amMon
8am
1am
9am
WORK
2am
10am
WORK
3am
11am
WORK
4am
12pm
WORK
5am
1pm
WORK
6am
2pm
WORK
NOW
7am
3pm
WORK
8am
4pm
WORK
9am
WORK
5pm
10am
WORK
6pm
11am
WORK
7pm
12pm
WORK
8pm
1pm
WORK
9pm
2pm
WORK
10pm
3pm
WORK
11pm
4pm
WORK
12amTue ·+1d
5pm
1amTue ·+1d
6pm
2amTue ·+1d
7pm
3amTue ·+1d
8pm
4amTue ·+1d
9pm
5amTue ·+1d
10pm
6amTue ·+1d
11pm
7amTue ·+1d
daylightnightworking hoursoverlap
Best time to meet
Closest workable window
Just outside the working window — early on one side, late on the other.
Greenwich Mean Time
7am–11am
=
Japan Standard Time
3pm–7pm
Popular conversions

Quick reference.

9amGreenwich Mean Time=5pmJapan Standard Time
12pmGreenwich Mean Time=8pmJapan Standard Time
3pmGreenwich Mean Time=11pmJapan Standard Time
5pmGreenwich Mean Time=1amJapan Standard Time · next day
9pmGreenwich Mean Time=5amJapan Standard Time · next day
In context

What each side covers.

Greenwich Mean Time
BST · UTC+01:00
7:43am
Cities on this clock
Japan Standard Time
JST · UTC+09:00
3:43pm
Cities on this clock

Frequently asked

Quick answers about converting between Greenwich Mean Time and Japan Standard Time. Can't find what you need? Email [email protected].

What is the time difference between Greenwich Mean Time and Japan Standard Time?
Greenwich Mean Time is 8 hours behind Japan Standard Time right now. We always show the live, daylight-saving-correct difference, so this figure already accounts for whichever side is observing summer time today.
When it's 12am in Greenwich Mean Time, what time is it in Japan Standard Time?
12am in Greenwich Mean Time is 8am in Japan Standard Time. That's early morning in Japan Standard Time, before the typical working day begins. Use the hour-by-hour table above to read any other time across.
What's the best time for a call between Greenwich Mean Time and Japan Standard Time?
There's no comfortable 9-to-5 overlap between Greenwich Mean Time and Japan Standard Time — they sit on opposite sides of the planet's working day. Plan for an early or late call on one side, or hand work off asynchronously.
Does this account for daylight saving time?
Yes. We track every clock change in both places, so the abbreviations you see — BST and JST — are the ones actually in effect right now, not a fixed all-year value. When either side changes its clocks, this page updates automatically.
Why is the date sometimes different on each side?
When two places are far enough apart, the same moment can fall on different calendar days. That is why some conversions are marked "previous day" or "next day" — it is the same instant in time, read off two clocks that crossed midnight at different points.