JST to Portsmouth Time Converter
GMT is 9 hours behind JST. 9:00 AM JST = 12:00 AM GMT.
GMT is 9 hours behind JST at the moment. To convert JST to Portsmouth Time, subtract 9 hours from the JST time: 9:00 AM JST = 12:00 AM GMT.
JST (Japan Time) is used in Japan. Portsmouth Time (Portsmouth time) is used in Portsmouth, UK.
JST to Portsmouth Time time conversion table
JST to Portsmouth Time on 8 Nov 2026. Today's date. Highlighted rows are 9 AM–5 PM in both places.
| JST | Portsmouth Time |
|---|---|
| 12:00 AM | 3:00 PM−1 |
| 1:00 AM | 4:00 PM−1 |
| 2:00 AM | 5:00 PM−1 |
| 3:00 AM | 6:00 PM−1 |
| 4:00 AM | 7:00 PM−1 |
| 5:00 AM | 8:00 PM−1 |
| 6:00 AM | 9:00 PM−1 |
| 7:00 AM | 10:00 PM−1 |
| JST | Portsmouth Time |
|---|---|
| 8:00 AM | 11:00 PM−1 |
| 9:00 AM | 12:00 AM |
| 10:00 AM | 1:00 AM |
| 11:00 AM | 2:00 AM |
| 12:00 PM | 3:00 AM |
| 1:00 PM | 4:00 AM |
| 2:00 PM | 5:00 AM |
| 3:00 PM | 6:00 AM |
| JST | Portsmouth Time |
|---|---|
| 4:00 PM | 7:00 AM |
| 5:00 PM | 8:00 AM |
| 6:00 PM | 9:00 AM |
| 7:00 PM | 10:00 AM |
| 8:00 PM | 11:00 AM |
| 9:00 PM | 12:00 PM |
| 10:00 PM | 1:00 PM |
| 11:00 PM | 2:00 PM |
Conversion table from JST to Portsmouth Time for 8 Nov 2026. A tick marks hours that fall between 9 AM and 5 PM in both places. +1 means the next day in Portsmouth Time, −1 the previous day.
- ✓ marks 9 AM–5 PM in both places
- Greyed times are night in the destination (10 PM–6 AM)
How to convert JST to Portsmouth Time
Subtract 9 hours from the JST time to get Portsmouth Time.
Example: 9:00 AM JST = 12:00 AM GMT.
Across midnight: 1:00 AM JST = 4:00 PM GMT (previous day). The date changes, so always check the day as well as the hour.
Time difference between JST and Portsmouth Time
The time difference between JST and Portsmouth Time is not the same all year, because the two sides change for daylight saving time on different dates. In 2026 it works out like this:
- 1 Jan 2026 – 28 Mar 2026: Portsmouth Time is 9 hours behind of JST.
- 29 Mar 2026 – 24 Oct 2026: Portsmouth Time is 8 hours behind of JST.
- 25 Oct 2026 – 31 Dec 2026: Portsmouth Time is 9 hours behind of JST.
JST and Portsmouth Time during daylight saving time
- JST does not observe daylight saving time; it stays on UTC+9 all year.
- Portsmouth Time next changes on 28 Mar 2027: clocks go forward one hour at 00:59 local time, from GMT (UTC+0) to BST (UTC+1).
Best time for a meeting between JST and Portsmouth Time
JST and Portsmouth Time have no shared 9 AM–5 PM window. The earliest slot that is reasonable on both sides is 7:00 AM JST, which is 10:00 PM GMT.
JST to Portsmouth Time FAQ
What is the time difference between JST and Portsmouth Time?
Right now GMT is 9 hours behind JST. The gap changes 3 times in 2026 because the two sides switch to daylight saving time on different dates.
What is 9 AM JST in Portsmouth Time?
9:00 AM JST is 12:00 AM GMT.
What is 12 PM (noon) JST in Portsmouth Time?
12:00 PM JST is 3:00 AM GMT.
Is Portsmouth Time ahead of or behind JST?
GMT is 9 hours behind JST, so it is earlier in Portsmouth Time than in JST.
Does JST change for daylight saving time?
No. JST stays on the same offset all year, so conversions never shift for daylight saving time.
Does Portsmouth Time change for daylight saving time?
Yes. Portsmouth Time next changes on 28 Mar 2027, when clocks go forward one hour from GMT to BST.
What is the best time for a meeting between JST and Portsmouth Time?
JST and Portsmouth Time have no shared 9 AM–5 PM window. The earliest slot that is reasonable on both sides is 7:00 AM JST, which is 10:00 PM GMT.
Related conversions
Convert Portsmouth Time to JST
Convert JST to other time zones
Convert other time zones to Portsmouth Time
Learn more
Updated 8 November 2026. Time zone data: IANA tz database.