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GMT to JST — Japan Standard Time is 9 hours ahead

Japan Standard Time (JST) is 9 hours ahead of Greenwich Mean Time (GMT) while both are on standard time. Once daylight saving starts the gap becomes 8 hours ahead, so any recurring meeting between these two regions moves by an hour twice a year.

Standard time

9 hours ahead

Applies while neither zone is on daylight saving — broadly November to March in the northern hemisphere.

Daylight saving

8 hours ahead

Applies while the clocks are forward. This pair does not keep a constant gap, so check the date.

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How the two zones line up

Greenwich Mean Time sits at UTC+0 in winter and UTC+1 in summer. Japan Standard Time sits at UTC+9 all year. The difference between those two offsets is the number you add or subtract.

Daylight saving

Standard working days do not overlap at all. One side will need to take the call early or late, so alternate who makes the sacrifice.

Where this conversion gets used

  • Supplier and factory calls
  • offshore delivery teams
  • shipping cut-offs
  • remote hiring interviews

GMT to JST — every hour

Both columns are computed from the IANA database, so they follow the real transition dates.

GMTJST — standardJST — daylight saving
12:00 am9:00 am8:00 am
1:00 am10:00 am9:00 am
2:00 am11:00 am10:00 am
3:00 am12:00 pm11:00 am
4:00 am1:00 pm12:00 pm
5:00 am2:00 pm1:00 pm
6:00 am3:00 pm2:00 pm
7:00 am4:00 pm3:00 pm
8:00 am5:00 pm4:00 pm
9:00 am6:00 pm5:00 pm
10:00 am7:00 pm6:00 pm
11:00 am8:00 pm7:00 pm
12:00 pm9:00 pm8:00 pm
1:00 pm10:00 pm9:00 pm
2:00 pm11:00 pm10:00 pm
3:00 pm12:00 am (next day)11:00 pm
4:00 pm1:00 am (next day)12:00 am (next day)
5:00 pm2:00 am (next day)1:00 am (next day)
6:00 pm3:00 am (next day)2:00 am (next day)
7:00 pm4:00 am (next day)3:00 am (next day)
8:00 pm5:00 am (next day)4:00 am (next day)
9:00 pm6:00 am (next day)5:00 am (next day)
10:00 pm7:00 am (next day)6:00 am (next day)
11:00 pm8:00 am (next day)7:00 am (next day)

Questions people ask

9 hours ahead during standard time, and 8 hours ahead while daylight saving is running.

Related conversions

EST to AESTEST to JSTGMT to AESTPST to JST

All conversions →

Booking something recurring?

A fixed clock time drifts when either side changes its clocks. Our guides explain how to stop that happening.

Read the DST guidePlan a meeting