ADT to JST Time Converter

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

ADT to JST Conversion Table

Major Cities Using ADT and JST

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

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

How many hours between ADT and JST?

ADT is UTC-3 and JST is UTC+9, a difference of 12 hours. JST is ahead of ADT. 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: ADT ↔ JST

Assuming a 9:00 AM – 5:00 PM workday on each side, there is no full 9–5 overlap between adt and jst — 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 ADT observe Daylight Saving Time?

Atlantic Daylight Time (ADT) is based on the America/Halifax 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 ADT in JST?

When it is 9:00 AM in Atlantic Daylight Time (ADT, UTC-3), it is 9:00 PM in Japan Standard Time (JST). 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 ADT to JST Converter

1. Type or drag any time in the ADT input above — the JST 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 JST to ADT for the reverse.

Related ADT Converters

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

Related JST Converters

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

More Time Tools

• All Time Zone Converters — browse every supported pair
• About ADT (Atlantic Daylight Time) — current time, cities, DST rules
• About JST (Japan Standard 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