JST to Tehran
-5h 30mJST
JSTSOURCETehran
IRSTGreen rows indicate typical business hours (9 AM - 5 PM)
JST and IRST on the World Map
The map below highlights the JST (Japan Standard Time) and IRST (Iran Standard Time) timezone regions across the globe.
JST – Japan Standard Time
UTC+09:00Japan Standard Time (JST) is the time zone for Japan, 9 hours ahead of UTC.
- •Japan does not observe daylight saving time.
- •Tokyo is the most populous metropolitan area in the world.
- •The Tokyo Stock Exchange operates from 9:00 AM to 3:00 PM JST.
- •JST is 14 hours ahead of EST and 9 hours ahead of GMT.
IRST – Iran Standard Time
UTC+03:30Iran Standard Time (IRST) is the time zone for Iran, 3 hours and 30 minutes ahead of UTC.
- •IRST is one of only a few time zones with a 30-minute offset.
- •Iran observes daylight saving time, switching to IRDT (UTC+04:30).
- •Tehran has a metropolitan population of over 16 million.
About Tehran
WikipediaTehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
Iran Standard Time (IRST) is one of few timezones with a 30-minute offset (UTC+3:30).
JST to Tehran Time Difference – Complete Guide
JST runs on Japan Standard Time (JST) at UTC+09:00. Tehran runs on Iran Standard Time (IRST) at UTC+03:30. That puts JST 5 hours 30 minutes behind Tehran — a difference of -5h 30m at the current offsets.
In practice, when it is 9:00 AM in JST it is 3:30 AM in Tehran. Midnight in JST is 6:30 PM in Tehran. Neither zone observes daylight saving time, so the offset between them stays constant all year.
JST to Tehran time conversion table
| JST (JST) | Tehran (IRST) | Day |
|---|---|---|
| 12:00 AM | 6:30 PM | previous day |
| 6:00 AM | 12:30 AM | same day |
| 7:00 AM | 1:30 AM | same day |
| 8:00 AM | 2:30 AM | same day |
| 9:00 AM | 3:30 AM | same day |
| 12:00 PM | 6:30 AM | same day |
| 3:00 PM | 9:30 AM | same day |
| 5:00 PM | 11:30 AM | same day |
| 6:00 PM | 12:30 PM | same day |
| 9:00 PM | 3:30 PM | same day |
Why people convert JST to Tehran time
- Scheduling a call from JST to Tehran: a 10:00 AM start in JST lands at 4:30 AM in Tehran, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both JST and Tehran are inside the 9-to-5 working day between 2:30 PM and 5:00 PM JST time (9:00 AM–11:30 AM IRST). That is roughly 2 hours 30 minutes of usable overlap.
- Keeping family and friends in sync: knowing that 8:00 PM in JST is 2:30 PM in Tehran makes it easy to avoid calling at 3 AM.
- Always state the zone abbreviation, not just the hour. "3:00 PM JST" is unambiguous; "3 PM" across a -5h 30m gap is not.
- Block 2:30 PM–5:00 PM JST as the recurring meeting window if you work primarily from JST and need Tehran colleagues present.
About JST (Japan Standard Time)
Japan Standard Time (JST) is the standard time zone for all of Japan. Japan does not observe daylight saving time. JST is 9 hours ahead of UTC and 14 hours ahead of EST. The Tokyo Stock Exchange, the world's third largest by market capitalization, operates on JST. South Korea uses the same offset (KST) but it is a distinct time zone.
About IRST (Iran Standard Time)
Iran Standard Time (IRST) is one of the few time zones with a 30-minute offset. Iran observes daylight saving time (IRDT, UTC+04:30) from late March to late September. Tehran, the capital, is one of the largest cities in the Middle East.
Best time to call between JST and Tehran
Both JST and Tehran sit inside the 9 AM – 5 PM working day between 2:30 PM–5:00 PM JST, which is 9:00 AM–11:30 AM IRST. That gives roughly 2 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
JST and Tehran overlap for about 2 hours during the working day — enough for meetings if you avoid the edges of the window.
JST is 5 hours 30 minutes behind Tehran (JST UTC+09:00 → IRST UTC+03:30). The shared working window is 2:30 PM–5:00 PM JST. Remember to re-check around daylight-saving transitions.
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between JST and Tehran?
JST (JST, UTC+09:00) is 5 hours 30 minutes behind Tehran (IRST, UTC+03:30). The gap is currently -5h 30m.
How do I convert JST time to Tehran time?
Add -5h 30m to JST local time. For example, 9:00 AM in JST is 3:30 AM in Tehran.
What time is it in Tehran right now?
Tehran uses IRST at UTC+03:30. Use the live converter at the top of this page — it updates in real time and already accounts for the -5h 30m offset from JST.
What is the best time to call Tehran from JST?
Call between 2:30 PM and 5:00 PM JST — that maps to 9:00 AM–11:30 AM IRST and keeps both parties inside the working day.
Which is behind, JST or Tehran?
JST is 5 hours 30 minutes behind Tehran. When it is 12:00 PM in JST it is 6:30 AM in Tehran.
Do JST and Tehran use different time zones?
JST uses JST at UTC+09:00, while Tehran (Iran) uses IRST at UTC+03:30. The IANA identifiers are Asia/Tokyo and Asia/Tehran.
Does daylight saving time affect the JST–Tehran difference?
Neither zone observes daylight saving time, so the -5h 30m offset between JST and Tehran is fixed all year.
Which other cities share JST's time zone?
JST also covers Tokyo, Osaka, Yokohama, Nagoya, Sapporo, Kyoto, Kobe, Fukuoka and 1 more.
Which countries use JST, JST's zone?
JST is used in Japan.
Is there a day difference between JST and Tehran?
Not normally. The -5h 30m gap only pushes the date over the previous day.
What is the time difference between JST and Tehran?
Tehran is -5h 30m from JST.
What timezone is JST in?
JST operates on its local timezone.
What timezone is Tehran in?
Tehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
What are the business hours in Tehran?
Standard business hours in Tehran are 8:00 AM - 4:00 PM IRST.
Which countries use JST (Japan Standard Time)?
JST is used in Japan.
Does JST observe daylight saving time?
No, JST does not observe daylight saving time and remains at UTC+09:00 year-round.
What are some interesting facts about JST?
Japan does not observe daylight saving time. Tokyo is the most populous metropolitan area in the world.
Which cities are in the IRST timezone?
Major cities in the IRST timezone include Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.
What is the UTC offset for IRST?
Iran Standard Time (IRST) is at UTC+03:30. During daylight saving time, it shifts to IRDT.
What should I know about the IRST timezone?
IRST is one of only a few time zones with a 30-minute offset. Iran observes daylight saving time, switching to IRDT (UTC+04:30).
When is it midnight in JST, what time is it in Tehran?
When it is 12:00 AM (midnight) in JST (JST), it is -5h 30m later in Tehran (IRST).
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