This JST to GMT converter turns any time in Japan Standard Time (JST) into Greenwich Mean Time (GMT), using your device clock so daylight saving is applied automatically. GMT is 9 hours behind JST. JST is UTC+9; GMT is UTC+0.
JST covers Tokyo, Osaka; GMT covers Accra, Dakar, London in winter. Neither zone observes daylight saving time, so the difference is the same every day of the year.
JST and GMT UTC offsets
JST
UTC+9
Japan Standard Time
No daylight saving time
GMT
UTC+0
Greenwich Mean Time
No daylight saving time
JST to GMT conversion table
| JST | GMT |
|---|---|
| 12 am | 3 pmprevious day |
| 3 am | 6 pmprevious day |
| 6 am | 9 pmprevious day |
| 8 am | 11 pmprevious day |
| 9 am | 12 am |
| 10 am | 1 am |
| 11 am | 2 am |
| 12 pm | 3 am |
| 1 pm | 4 am |
| 2 pm | 5 am |
| 3 pm | 6 am |
| 4 pm | 7 am |
| 5 pm | 8 am |
| 6 pm | 9 am |
| 8 pm | 11 am |
| 10 pm | 1 pm |
Frequently asked questions
What is the time difference between JST and GMT?
GMT is 9 hours behind JST. That comes from the UTC offsets: JST is UTC+9 and GMT is UTC+0. For example, 9 am JST = 12 am GMT.
Is GMT ahead of or behind JST?
GMT is 9 hours behind JST, so when it is noon in JST it is 3 am in GMT. Ahead means the clock there already shows a later time; a call at 5 pm JST lands at 8 am GMT.
Does JST or GMT observe daylight saving time in 2026?
No. Neither JST nor GMT changes its clocks, so the 9 hours difference holds every day of the year. That makes recurring meetings between Tokyo and Accra easy to keep at a fixed local time on both ends.
What is the best time for a meeting between JST and GMT?
Office hours (9 am to 5 pm) do not overlap at all with a 9 hours difference. The least painful options are early morning in GMT or early evening in JST; for example 8 am JST = 11 pm GMT the previous day and 6 pm JST = 9 am GMT. Rotate the inconvenient slot between the two sides for recurring calls.
Which cities use JST and GMT?
JST (Japan Standard Time) is used in Tokyo, Osaka. GMT (Greenwich Mean Time) is used in Accra, Dakar, London in winter. Note that the United Kingdom is only on GMT in winter; from late March to late October London runs on British Summer Time, one hour ahead, so use the BST pages for UK business hours in summer.