Tokyo to IRST
-5h 30mTokyo
JSTSOURCEIRST
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 Tokyo
WikipediaTokyo operates on Japan Standard Time (JST), which is 14 hours ahead of New York. As Asia's largest financial hub, Tokyo trading hours are crucial for global markets.
The Tokyo subway system moves approximately 8.7 million passengers daily.
Time Conversion Guide: Tokyo to IRST
Tokyo runs on Japan Standard Time (JST) at UTC+09:00. IRST runs on Iran Standard Time (IRST) at UTC+03:30. That puts Tokyo 5 hours 30 minutes behind IRST — a difference of -5h 30m at the current offsets.
In practice, when it is 9:00 AM in Tokyo it is 3:30 AM in IRST. Midnight in Tokyo is 6:30 PM in IRST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
Tokyo to IRST time conversion table
| Tokyo (JST) | IRST (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 Tokyo to IRST time
- Scheduling a call from Tokyo to IRST: a 10:00 AM start in Tokyo lands at 4:30 AM in IRST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both Tokyo and IRST 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.
- Watching a live event or market open: Tokyo viewers need 3:30 AM in IRST to catch a 9:00 AM start there, and 5:30 AM if the event is anchored to Tokyo.
- 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 Tokyo and need IRST 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 Tokyo and IRST
Both Tokyo and IRST 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
Tokyo and IRST overlap for about 2 hours during the working day — enough for meetings if you avoid the edges of the window.
Tokyo is 5 hours 30 minutes behind IRST (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 Tokyo and IRST?
Tokyo (JST, UTC+09:00) is 5 hours 30 minutes behind IRST (IRST, UTC+03:30). The gap is currently -5h 30m.
How do I convert Tokyo time to IRST time?
Add -5h 30m to Tokyo local time. For example, 9:00 AM in Tokyo is 3:30 AM in IRST.
What time is it in IRST right now?
IRST 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 Tokyo.
What is the best time to call IRST from Tokyo?
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, Tokyo or IRST?
Tokyo is 5 hours 30 minutes behind IRST. When it is 12:00 PM in Tokyo it is 6:30 AM in IRST.
Do Tokyo and IRST use different time zones?
Tokyo (Japan) uses JST at UTC+09:00, while IRST uses IRST at UTC+03:30. The IANA identifiers are Asia/Tokyo and Asia/Tehran.
Does daylight saving time affect the Tokyo–IRST difference?
Neither zone observes daylight saving time, so the -5h 30m offset between Tokyo and IRST is fixed all year.
Which other cities share Tokyo's time zone?
JST also covers Tokyo, Osaka, Yokohama, Nagoya, Sapporo, Kyoto, Kobe, Fukuoka and 1 more.
Which countries use JST, Tokyo's zone?
JST is used in Japan.
Is there a day difference between Tokyo and IRST?
Not normally. The -5h 30m gap only pushes the date over the previous day.
What is the time difference between Tokyo and IRST?
IRST is -5h 30m from Tokyo.
What timezone is Tokyo in?
Tokyo operates on Japan Standard Time (JST), which is 14 hours ahead of New York. As Asia's largest financial hub, Tokyo trading hours are crucial for global markets.
What timezone is IRST in?
IRST operates on its local timezone.
What are the business hours in Tokyo?
Standard business hours in Tokyo are 9:00 AM - 6:00 PM JST.
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 Tokyo, what time is it in IRST?
When it is 12:00 AM (midnight) in Tokyo (JST), it is -5h 30m later in IRST (IRST).
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