JST to AST Converter & Meeting Planner
Quick answer: 9:00 AM JST = 8:00 PM AST (fixed +09:00 standard offset — not DST-adjusted). Use the interactive converter below for DST-aware local-time scheduling.
Planning a call or meeting between Japan Standard Time (JST) and Atlantic Standard Time (AST)? You need to account for the standard time difference. Atlantic Standard Time is normally 13 hours behind Japan Standard Time. Whether you are coordinating between teams in Tokyo and Osaka and Halifax and San Juan, our live tool has you covered. Use our interactive overlap studio below to find the perfect waking hours for both regions, taking into account any seasonal Daylight Saving Time (DST) changes.
24-Hour Conversion Table
Quick reference: 12:00 AM JST = 11:00 AM AST. The full 24-hour JST to AST table below uses fixed standard offsets for exact abbreviation searches.
Example: 3:00 PM JST = 2:00 AM AST.
| JST Time | AST Time |
|---|---|
| 12:00 AM (00:00) | 11:00 AM (11:00)-1 day |
| 1:00 AM (01:00) | 12:00 PM (12:00)-1 day |
| 2:00 AM (02:00) | 1:00 PM (13:00)-1 day |
| 3:00 AM (03:00) | 2:00 PM (14:00)-1 day |
| 4:00 AM (04:00) | 3:00 PM (15:00)-1 day |
| 5:00 AM (05:00) | 4:00 PM (16:00)-1 day |
| 6:00 AM (06:00) | 5:00 PM (17:00)-1 day |
| 7:00 AM (07:00) | 6:00 PM (18:00)-1 day |
| 8:00 AM (08:00) | 7:00 PM (19:00)-1 day |
| 9:00 AM (09:00) | 8:00 PM (20:00)-1 day |
| 10:00 AM (10:00) | 9:00 PM (21:00)-1 day |
| 11:00 AM (11:00) | 10:00 PM (22:00)-1 day |
| 12:00 PM (12:00) | 11:00 PM (23:00)-1 day |
| 1:00 PM (13:00) | 12:00 AM (00:00) |
| 2:00 PM (14:00) | 1:00 AM (01:00) |
| 3:00 PM (15:00) | 2:00 AM (02:00) |
| 4:00 PM (16:00) | 3:00 AM (03:00) |
| 5:00 PM (17:00) | 4:00 AM (04:00) |
| 6:00 PM (18:00) | 5:00 AM (05:00) |
| 7:00 PM (19:00) | 6:00 AM (06:00) |
| 8:00 PM (20:00) | 7:00 AM (07:00) |
| 9:00 PM (21:00) | 8:00 AM (08:00) |
| 10:00 PM (22:00) | 9:00 AM (09:00) |
| 11:00 PM (23:00) | 10:00 AM (10:00) |
Best time to call Halifax from Tokyo
For most work calls, compare the normal business day in Tokyo (JST) with the business day in Halifax (AST). JST commonly covers East Asia, while AST is mainly associated with North America, Caribbean.
⚠️ Note: 2026-07-05 is not a normal workday in one or both regions based on their configured calendar. The overlap below should be treated as a reference, not a guaranteed office-hours window.
⚠️ There is no clean same-day business-hours overlap on 2026-07-05. A practical compromise is around 9:00 PM JST, which reaches 9:00 AM AST near the start of their workday.
- DST Safety: JST or AST may shift during Daylight Saving Time. Always confirm the converted time for your specific date.
- Tokyo Stock Exchange (TSE): 09:00-15:00 local time in Tokyo.
🔥 Popular JST & AST Converters
Frequently searched time zone conversions related to your search.
Related Time Converters
Explore nearby time zone offsets and reverse conversions related to JST and AST.
Frequently Asked Questions
What is the time difference between JST and AST?
During standard time, Atlantic Standard Time is 13 hours behind Japan Standard Time.
Does Japan observe Daylight Saving Time?
Japan has not observed Daylight Saving Time since 1951, when the practice introduced during the Allied occupation was abolished by the Japanese government. JST has remained fixed at UTC+9:00 ever since, and there is no current legislation to reintroduce DST in Japan.
Is JST the same as Korean Standard Time (KST)?
Yes, South Korea's Korean Standard Time (KST) operates at the same UTC+9:00 offset as JST, and South Korea also does not observe Daylight Saving Time. The two countries share an identical clock year-round, which simplifies scheduling for the significant trade, technology, and cultural exchange between Tokyo and Seoul.
Does the Caribbean observe Daylight Saving Time?
The vast majority of Caribbean nations and territories — including Puerto Rico, the Dominican Republic, the US Virgin Islands, Trinidad and Tobago, and Barbados — do not observe Daylight Saving Time and remain on AST (UTC-4) year-round. This means these territories share the same clock as Halifax only during the Atlantic Standard Time window in winter, diverging by one hour once Canada and Bermuda advance to ADT each spring.
What is the difference between AST and ADT?
AST (Atlantic Standard Time) is the standard winter offset at UTC-4:00, observed from the first Sunday in November through the second Sunday in March across all AST regions. ADT (Atlantic Daylight Time) is the summer offset at UTC-3:00, applied by Eastern Canadian provinces and Bermuda when they advance their clocks by one hour during Daylight Saving Time.