AST to EST Time Converter

When it is 9:00 AM AST, it is 8:00 AM EST. Eastern Standard Time (EST, UTC-5) is 1 hour behind Atlantic Standard Time (AST, UTC-4). Your working-hours overlap window is 10:00 AM–5:00 PM AST (9:00 AM–4:00 PM EST).

AST to EST Conversion Table

Major Cities Using AST and EST

Atlantic Standard Time (AST): Halifax, Saint John, Moncton.

Eastern Standard Time (EST): New York, Washington D.C., Boston, Atlanta, Miami, Toronto.

How many hours between AST and EST?

AST is UTC-4 and EST is UTC-5, a difference of 1 hour. EST is behind AST. 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: AST ↔ EST

Assuming a 9:00 AM – 5:00 PM workday on each side, your working-hours overlap window is 10:00 am–5:00 pm ast (9:00 am–4:00 pm est). 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 AST observe Daylight Saving Time?

Atlantic Standard Time (AST) 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 AST in EST?

When it is 9:00 AM in Atlantic Standard Time (AST, UTC-4), it is 8:00 AM in Eastern Standard Time (EST). 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 AST to EST Converter

1. Type or drag any time in the AST input above — the EST 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 EST to AST for the reverse.

Related AST Converters

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

Related EST Converters

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

More Time Tools

• All Time Zone Converters — browse every supported pair
• About AST (Atlantic Standard Time) — current time, cities, DST rules
• About EST (Eastern 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