Tehran to JST
+5h 30mTehran
IRSTSOURCEJST
JSTGreen rows indicate typical business hours (9 AM - 5 PM)
IRST and JST on the World Map
The map below highlights the IRST (Iran Standard Time) and JST (Japan Standard Time) timezone regions across the globe.
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.
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.
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).
Everything You Need to Know About Tehran and JST Time
Tehran runs on Iran Standard Time (IRST) at UTC+03:30. JST runs on Japan Standard Time (JST) at UTC+09:00. That puts Tehran 5 hours 30 minutes ahead of JST — a difference of +5h 30m at the current offsets.
In practice, when it is 9:00 AM in Tehran it is 2:30 PM in JST. Midnight in Tehran is 5:30 AM in JST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
Tehran to JST time conversion table
| Tehran (IRST) | JST (JST) | Day |
|---|---|---|
| 12:00 AM | 5:30 AM | same day |
| 6:00 AM | 11:30 AM | same day |
| 7:00 AM | 12:30 PM | same day |
| 8:00 AM | 1:30 PM | same day |
| 9:00 AM | 2:30 PM | same day |
| 12:00 PM | 5:30 PM | same day |
| 3:00 PM | 8:30 PM | same day |
| 5:00 PM | 10:30 PM | same day |
| 6:00 PM | 11:30 PM | same day |
| 9:00 PM | 2:30 AM | next day |
Why people convert Tehran to JST time
- Scheduling a call from Tehran to JST: a 10:00 AM start in Tehran lands at 3:30 PM in JST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both Tehran and JST are inside the 9-to-5 working day between 9:00 AM and 11:30 AM IRST time (2:30 PM–5:00 PM JST). That is roughly 2 hours 30 minutes of usable overlap.
- Watching a live event or market open: Tehran viewers need 2:30 PM in JST to catch a 9:00 AM start there, and 6:30 PM if the event is anchored to Tehran.
- Always state the zone abbreviation, not just the hour. "3:00 PM IRST" is unambiguous; "3 PM" across a +5h 30m gap is not.
- Block 9:00 AM–11:30 AM IRST as the recurring meeting window if you work primarily from Tehran and need JST colleagues present.
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.
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.
Best time to call between Tehran and JST
Both Tehran and JST sit inside the 9 AM – 5 PM working day between 9:00 AM–11:30 AM IRST, which is 2:30 PM–5:00 PM JST. That gives roughly 2 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
Tehran and JST overlap for about 2 hours during the working day — enough for meetings if you avoid the edges of the window.
Tehran is 5 hours 30 minutes ahead of JST (IRST UTC+03:30 → JST UTC+09:00). The shared working window is 9:00 AM–11:30 AM IRST. 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 Tehran and JST?
Tehran (IRST, UTC+03:30) is 5 hours 30 minutes ahead of JST (JST, UTC+09:00). The gap is currently +5h 30m.
How do I convert Tehran time to JST time?
Add +5h 30m to Tehran local time. For example, 9:00 AM in Tehran is 2:30 PM in JST.
What time is it in JST right now?
JST uses JST at UTC+09:00. Use the live converter at the top of this page — it updates in real time and already accounts for the +5h 30m offset from Tehran.
What is the best time to call JST from Tehran?
Call between 9:00 AM and 11:30 AM IRST — that maps to 2:30 PM–5:00 PM JST and keeps both parties inside the working day.
Which is ahead, Tehran or JST?
Tehran is 5 hours 30 minutes ahead of JST. When it is 12:00 PM in Tehran it is 5:30 PM in JST.
Do Tehran and JST use different time zones?
Tehran (Iran) uses IRST at UTC+03:30, while JST uses JST at UTC+09:00. The IANA identifiers are Asia/Tehran and Asia/Tokyo.
Does daylight saving time affect the Tehran–JST difference?
Neither zone observes daylight saving time, so the +5h 30m offset between Tehran and JST is fixed all year.
Which other cities share Tehran's time zone?
IRST also covers Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.
Which countries use IRST, Tehran's zone?
IRST is used in Iran.
Is there a day difference between Tehran and JST?
Not normally. The +5h 30m gap only pushes the date over for late-evening times.
What is the time difference between Tehran and JST?
JST is +5h 30m from Tehran.
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 timezone is JST in?
JST operates on its local timezone.
What are the business hours in Tehran?
Standard business hours in Tehran are 8:00 AM - 4:00 PM IRST.
Which countries use IRST (Iran Standard Time)?
IRST is used in Iran.
Does IRST observe daylight saving time?
Yes, IRST switches to IRDT during summer months.
What are some interesting facts about IRST?
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).
Which cities are in the JST timezone?
Major cities in the JST timezone include Tokyo, Osaka, Yokohama, Nagoya, Sapporo, Kyoto, Kobe, Fukuoka.
What is the UTC offset for JST?
Japan Standard Time (JST) is at UTC+09:00.
What should I know about the JST timezone?
Japan does not observe daylight saving time. Tokyo is the most populous metropolitan area in the world.
When is it midnight in Tehran, what time is it in JST?
When it is 12:00 AM (midnight) in Tehran (IRST), it is +5h 30m later in JST (JST).
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