KST to AST Converter & Meeting Planner
Quick answer: 9:00 AM KST = 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 Korea Standard Time (KST) and Atlantic Standard Time (AST)? You need to account for the standard time difference. Atlantic Standard Time is normally 13 hours behind Korea Standard Time. Whether you are coordinating between teams in Seoul and Busan 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 KST = 11:00 AM AST. The full 24-hour KST to AST table below uses fixed standard offsets for exact abbreviation searches.
Example: 3:00 PM KST = 2:00 AM AST.
| KST 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 Seoul
For most work calls, compare the normal business day in Seoul (KST) with the business day in Halifax (AST). KST 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 KST, which reaches 9:00 AM AST near the start of their workday.
- DST Safety: KST or AST may shift during Daylight Saving Time. Always confirm the converted time for your specific date.
- Korea Exchange (KRX): 09:00-15:30 local time in Seoul.
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Frequently Asked Questions
What is the time difference between KST and AST?
During standard time, Atlantic Standard Time is 13 hours behind Korea Standard Time.
Does South Korea observe Daylight Saving Time?
South Korea does not observe Daylight Saving Time and has not done so since 1988, when DST was discontinued following the Seoul Summer Olympics. KST remains fixed at UTC+9:00 every day of the year, meaning the offset between Seoul and any DST-observing country shifts by one hour twice annually when those countries change their clocks.
Are KST and JST the same?
Yes, Korea Standard Time (KST) and Japan Standard Time (JST) share the identical UTC+9:00 offset, and neither country observes Daylight Saving Time. Seoul and Tokyo run on exactly the same clock year-round, which directly supports the deep semiconductor, automotive, and consumer electronics supply chain integration between the two economies.
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.