--:--:--
—
Seoul · Busan
Find the best shared slot in the world meeting planner.
Difference
AST vs KST
UTC → UTC
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—
San Juan · Barbados · Halifax (winter)
KST to AST converter
KST to AST Converter
Convert KST (Seoul) to AST (San Juan) now. Live clocks, the current time difference, and a simple meeting window — free.
Asia/Seoul
—
KST → AST
To · Atlantic Standard Time
—
America/Puerto_Rico
Interactive diagram
Watch KST convert into AST
Drag the Korea hour. Watch the Atlantic clock change.
Korea
9:00 AM KST
—
AST ← KST
Atlantic
—
Full-day chart
KST to AST hourly conversion chart
Full-day table. Tap a row to copy. Labels follow daylight saving.
| Korea | Atlantic | UTC offsets |
|---|
Meeting times
Best KST to AST meeting window
Find hours that work on both sides. Then save the slot to your calendar.
Follow along
Step-by-step KST to AST conversion
Four short steps to convert any KST time to AST.
Choose KST time
Select any hour in Korea Standard Time. Smart mode uses Asia/Seoul.
KST to AST conversion guide
KST to AST conversion guide
This KST to AST converter shows Atlantic Standard Time (UTC−4) for any Korea Standard Time (UTC+9) time. Use it to schedule between Seoul and San Juan. Choose Smart DST for live city clocks. Choose Fixed mode when you only want the KST and AST labels.
Korea
KST
UTC+9
Seoul · Busan
KST vs AST—
Atlantic
AST
UTC−4
San Juan · Barbados · Halifax (winter)
What is KST to AST conversion?
KST to AST conversion turns a KST clock into the matching AST time. Use it for calls, travel, and teams in Seoul and San Juan.
KST to AST time difference
AST is 13 hours behind KST. Subtract 13 hours from the KST time to get AST. The live clocks at the top show the current KST to AST gap.
KST vs AST
KST is UTC+9. AST is UTC−4. They are different names. If a region uses daylight saving, check the live labels.
KST to AST now / current time
Need kst to ast right now? Read the live clocks, or tap Use current time for an instant KST → AST result.
KST to AST time difference
Season / context — tap to explore
See how daylight saving can change this pair.
Korea—
—KST → AST
Atlantic—
Quick answers
Korea
Korea Standard Time (KST)
UTC+9
Korea Standard Time (KST) is UTC+9. Smart DST uses the city clock Asia/Seoul so daylight saving stays correct for Seoul · Busan.
- Cities: Seoul · Busan
- City clock: Asia/Seoul
- Fixed KST: UTC+9
- On this page it pairs with AST (UTC−4)
Atlantic
Atlantic Standard Time (AST)
UTC−4
Atlantic Standard Time (AST) is UTC−4. Smart DST uses America/Puerto_Rico for cities such as San Juan · Barbados · Halifax (winter).
- Cities: San Juan · Barbados · Halifax (winter)
- City clock: America/Puerto_Rico
- Fixed AST: UTC−4
- From KST: AST is 13 hours behind KST
KST to AST FAQ
Common KST to AST questions
What is the KST to AST time difference?
AST is 13 hours behind KST. Fixed labels: KST = UTC+9, AST = UTC−4. Subtract 13 hours from the KST time to get AST.
How do I convert KST to AST quickly?
Subtract 13 hours from the KST time to get AST. Example: 3:00 AM KST → 2:00 PM AST. Or use the live KST to AST converter above.
Is AST the same as KST?
No. KST is UTC+9 (Seoul · Busan). AST is UTC−4 (San Juan · Barbados · Halifax (winter)).
What is a good KST to AST meeting time?
AST is behind. Try 10:00 AM–3:00 PM KST. That is about 9:00 PM–2:00 AM AST. Use the meeting planner on this page to export an ICS or Google Calendar invite.
What cities use KST and AST?
KST is common in Seoul · Busan. AST is common in San Juan · Barbados · Halifax (winter). Smart DST uses Asia/Seoul and America/Puerto_Rico.