CEST to AST
-6hCEST
CESTSOURCEAST
ASTGreen rows indicate typical business hours (9 AM - 5 PM)
CEST and AST on the World Map
The map below highlights the CEST (Central European Summer Time) and AST (Atlantic Standard Time) timezone regions across the globe.
CEST – Central European Summer Time
UTC+02:00Central European Summer Time (CEST) is the daylight saving time in Central Europe, 2 hours ahead of UTC.
- •CEST runs from the last Sunday of March to the last Sunday of October.
- •The EU has voted to abolish clock changes but implementation has been delayed.
- •CEST shares the same offset as EET (UTC+02:00).
AST – Atlantic Standard Time
UTC-04:00Atlantic Standard Time (AST) is the time zone for the Canadian Atlantic provinces and the Caribbean, 4 hours behind UTC.
- •Puerto Rico uses AST year-round and does not observe DST.
- •AST is 1 hour ahead of EST.
- •Halifax, the capital of Nova Scotia, is the largest city in AST Canada.
Comparing Time Zones: CEST and AST
CEST runs on Central European Summer Time (CEST) at UTC+02:00. AST runs on Atlantic Standard Time (AST) at UTC-04:00. That puts CEST 6 hours behind AST — a difference of -6h at the current offsets.
In practice, when it is 9:00 AM in CEST it is 3:00 AM in AST. Midnight in CEST is 6:00 PM in AST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
CEST to AST time conversion table
| CEST (CEST) | AST (AST) | Day |
|---|---|---|
| 12:00 AM | 6:00 PM | previous day |
| 6:00 AM | 12:00 AM | same day |
| 7:00 AM | 1:00 AM | same day |
| 8:00 AM | 2:00 AM | same day |
| 9:00 AM | 3:00 AM | same day |
| 12:00 PM | 6:00 AM | same day |
| 3:00 PM | 9:00 AM | same day |
| 5:00 PM | 11:00 AM | same day |
| 6:00 PM | 12:00 PM | same day |
| 9:00 PM | 3:00 PM | same day |
Why people convert CEST to AST time
- Scheduling a call from CEST to AST: a 10:00 AM start in CEST lands at 4:00 AM in AST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both CEST and AST are inside the 9-to-5 working day between 3:00 PM and 5:00 PM CEST time (9:00 AM–11:00 AM AST). That is roughly 2 hours of usable overlap.
- Coordinating a CEST-based team with AST contacts: quoting times in the other side's local clock — not your own — removes the single biggest source of missed meetings.
- Always state the zone abbreviation, not just the hour. "3:00 PM CEST" is unambiguous; "3 PM" across a -6h gap is not.
- Block 3:00 PM–5:00 PM CEST as the recurring meeting window if you work primarily from CEST and need AST colleagues present.
About CEST (Central European Summer Time)
Central European Summer Time (CEST) is observed from the last Sunday of March to the last Sunday of October across most of Europe. During CEST, clocks are 2 hours ahead of UTC. The EU has debated abolishing seasonal clock changes since 2019.
About AST (Atlantic Standard Time)
Atlantic Standard Time (AST) covers Canada's Atlantic provinces (Nova Scotia, New Brunswick, Prince Edward Island, and most of Labrador), as well as several Caribbean nations. Puerto Rico and the US Virgin Islands use AST year-round without daylight saving time. The Canadian provinces switch to Atlantic Daylight Time (ADT) in summer.
Best time to call between CEST and AST
Both CEST and AST sit inside the 9 AM – 5 PM working day between 3:00 PM–5:00 PM CEST, which is 9:00 AM–11:00 AM AST. That gives roughly 2 hours of shared time — the safest window for a live call or meeting.
Business hours overlap
CEST and AST overlap for about 2 hours during the working day — enough for meetings if you avoid the edges of the window.
CEST is 6 hours behind AST (CEST UTC+02:00 → AST UTC-04:00). The shared working window is 3:00 PM–5:00 PM CEST. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
CEST
☀ Currently in DST
Standard: UTC+01:00 · DST: UTC+02:00
Clocks fall back on Sun, Oct 25, 2026
AST
☀ Currently in DST
Standard: UTC-04:00 · DST: UTC-03:00
Clocks fall back on Sun, Nov 1, 2026
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between CEST and AST?
CEST (CEST, UTC+02:00) is 6 hours behind AST (AST, UTC-04:00). The gap is currently -6h.
How do I convert CEST time to AST time?
Add -6h to CEST local time. For example, 9:00 AM in CEST is 3:00 AM in AST.
What time is it in AST right now?
AST uses AST at UTC-04:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -6h offset from CEST.
What is the best time to call AST from CEST?
Call between 3:00 PM and 5:00 PM CEST — that maps to 9:00 AM–11:00 AM AST and keeps both parties inside the working day.
Which is behind, CEST or AST?
CEST is 6 hours behind AST. When it is 12:00 PM in CEST it is 6:00 AM in AST.
Does daylight saving time affect the CEST–AST difference?
Neither zone observes daylight saving time, so the -6h offset between CEST and AST is fixed all year.
Which other cities share CEST's time zone?
CEST also covers Paris, Berlin, Rome, Madrid, Amsterdam, Vienna, Stockholm.
Which countries use CEST, CEST's zone?
CEST is used in Germany, France, Italy, Spain, Netherlands, Belgium, Austria, Switzerland and 3 more.
Is there a day difference between CEST and AST?
Not normally. The -6h gap only pushes the date over the previous day.
What is the time difference between CEST and AST?
AST is -6h from CEST.
What timezone is CEST in?
CEST operates on its local timezone.
What timezone is AST in?
AST operates on its local timezone.
Which countries use CEST (Central European Summer Time)?
CEST is used in Germany, France, Italy, Spain, Netherlands, Belgium, and 5 more countries.
Does CEST observe daylight saving time?
Yes, CEST switches to CET during summer months.
What are some interesting facts about CEST?
CEST runs from the last Sunday of March to the last Sunday of October. The EU has voted to abolish clock changes but implementation has been delayed.
Which cities are in the AST timezone?
Major cities in the AST timezone include Halifax, San Juan, Santo Domingo, Caracas, La Paz, Fredericton, Charlottetown.
What is the UTC offset for AST?
Atlantic Standard Time (AST) is at UTC-04:00. During daylight saving time, it shifts to ADT.
What should I know about the AST timezone?
Puerto Rico uses AST year-round and does not observe DST. AST is 1 hour ahead of EST.
When is it midnight in CEST, what time is it in AST?
When it is 12:00 AM (midnight) in CEST (CEST), it is -6h later in AST (AST).
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See every conversion from CEST →·See every conversion from AST →