JST to ADT Time Converter

When it is 9:00 AM JST, it is 9:00 PM ADT. Atlantic Daylight Time (ADT, UTC-3) is 12 hours behind Japan Standard Time (JST, UTC+9). There is no full 9–5 overlap between JST and ADT — teams typically rotate early or late meetings.

JST to ADT Conversion Table

Major Cities Using JST and ADT

Japan Standard Time (JST): Tokyo, Osaka, Kyoto, Yokohama.

Atlantic Daylight Time (ADT): Halifax, Saint John, Moncton.

How many hours between JST and ADT?

JST is UTC+9 and ADT is UTC-3, a difference of 12 hours. ADT is behind JST. This difference can shift by an hour in either direction during Daylight Saving Time transitions — if one zone observes DST and the other doesn't, the offset narrows or widens for part of the year.

Business Hours Overlap: JST ↔ ADT

Assuming a 9:00 AM – 5:00 PM workday on each side, there is no full 9–5 overlap between jst and adt — teams typically rotate early or late meetings. To visualize this instantly for any pair of cities, use the visual meeting planner or the timezone overlap finder — both highlight the green overlap window on a live timeline.

Does JST observe Daylight Saving Time?

Japan Standard Time (JST) is based on the Asia/Tokyo IANA timezone. DST observance depends on the jurisdiction — for example, most of the continental US switches between standard and daylight time, while India, Japan, and most of Southeast Asia do not observe DST at all. WorldClock.lol uses the authoritative IANA timezone database, so every conversion automatically accounts for the correct DST rules on the date you're converting.

When is 9 AM JST in ADT?

When it is 9:00 AM in Japan Standard Time (JST, UTC+9), it is 9:00 PM in Atlantic Daylight Time (ADT). For other times of day, scan the conversion table above or drop into the interactive converter to pick an exact minute. The converter handles both standard and daylight variants correctly.

How to Use This JST to ADT Converter

1. Type or drag any time in the JST input above — the ADT equivalent updates instantly.
2. Check the day indicator. When the converted time crosses midnight, the tool shows +1 day or −1 day so you don't book a meeting on the wrong date.
3. Copy the shareable URL to send the specific conversion to a colleague — the link preserves your exact selection.
4. Switch directions by swapping the input zones, or open ADT to JST for the reverse.

Related JST Converters

• JST to EST
• JST to PST
• JST to GMT
• JST to UTC
• JST to IST
• JST to CET

Related ADT Converters

• EST to ADT
• PST to ADT
• GMT to ADT
• UTC to ADT
• IST to ADT
• CET to ADT

More Time Tools

• All Time Zone Converters — browse every supported pair
• About JST (Japan Standard Time) — current time, cities, DST rules
• About ADT (Atlantic Daylight Time) — current time, cities, DST rules
• Meeting Planner — find the best time for a multi-city meeting
• Best Time to Call — optimal calling windows between any two cities
• UTC Time Now — the reference point for every conversion
• DST Schedule 2026 — every daylight-saving transition this year