PDT to AST
+3hPDT
PDTSOURCEAST
ASTGreen rows indicate typical business hours (9 AM - 5 PM)
PDT and AST on the World Map
The map below highlights the PDT (Pacific Daylight Time) and AST (Atlantic Standard Time) timezone regions across the globe.
PDT – Pacific Daylight Time
UTC-07:00Pacific Daylight Time (PDT) is the daylight saving offset on the US/Canada Pacific coast, 7 hours behind UTC.
- •PDT aligns with MST at UTC-07:00.
- •Tech company earnings calls often reference PDT/PST times.
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.
Understanding the +3h Gap: PDT vs AST
PDT runs on Pacific Daylight Time (PDT) at UTC-07:00. AST runs on Atlantic Standard Time (AST) at UTC-04:00. That puts PDT 3 hours ahead of AST — a difference of +3h at the current offsets.
In practice, when it is 9:00 AM in PDT it is 12:00 PM in AST. Midnight in PDT is 3:00 AM in AST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
PDT to AST time conversion table
| PDT (PDT) | AST (AST) | Day |
|---|---|---|
| 12:00 AM | 3:00 AM | same day |
| 6:00 AM | 9:00 AM | same day |
| 7:00 AM | 10:00 AM | same day |
| 8:00 AM | 11:00 AM | same day |
| 9:00 AM | 12:00 PM | same day |
| 12:00 PM | 3:00 PM | same day |
| 3:00 PM | 6:00 PM | same day |
| 5:00 PM | 8:00 PM | same day |
| 6:00 PM | 9:00 PM | same day |
| 9:00 PM | 12:00 AM | next day |
Why people convert PDT to AST time
- Scheduling a call from PDT to AST: a 10:00 AM start in PDT lands at 1:00 PM in AST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both PDT and AST are inside the 9-to-5 working day between 9:00 AM and 2:00 PM PDT time (12:00 PM–5:00 PM AST). That is roughly 5 hours of usable overlap.
- Coordinating a PDT-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 PDT" is unambiguous; "3 PM" across a +3h gap is not.
- Block 9:00 AM–2:00 PM PDT as the recurring meeting window if you work primarily from PDT and need AST colleagues present.
About PDT (Pacific Daylight Time)
Pacific Daylight Time (PDT) is observed from March to November on the Pacific coast. During PDT, the west coast is 7 hours behind UTC and only 2 hours behind the east coast's EDT.
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 PDT and AST
Both PDT and AST sit inside the 9 AM – 5 PM working day between 9:00 AM–2:00 PM PDT, which is 12:00 PM–5:00 PM AST. That gives roughly 5 hours of shared time — the safest window for a live call or meeting.
Business hours overlap
PDT and AST share 5 hours of working-hours overlap (9:00 AM–2:00 PM PDT), so scheduling a live meeting is straightforward.
PDT is 3 hours ahead of AST (PDT UTC-07:00 → AST UTC-04:00). The shared working window is 9:00 AM–2:00 PM PDT. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
PDT
☀ Currently in DST
Standard: UTC-08:00 · DST: UTC-07:00
Clocks fall back on Sun, Nov 1, 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 PDT and AST?
PDT (PDT, UTC-07:00) is 3 hours ahead of AST (AST, UTC-04:00). The gap is currently +3h.
How do I convert PDT time to AST time?
Add +3h to PDT local time. For example, 9:00 AM in PDT is 12:00 PM 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 +3h offset from PDT.
What is the best time to call AST from PDT?
Call between 9:00 AM and 2:00 PM PDT — that maps to 12:00 PM–5:00 PM AST and keeps both parties inside the working day.
Which is ahead, PDT or AST?
PDT is 3 hours ahead of AST. When it is 12:00 PM in PDT it is 3:00 PM in AST.
Does daylight saving time affect the PDT–AST difference?
Neither zone observes daylight saving time, so the +3h offset between PDT and AST is fixed all year.
Which other cities share PDT's time zone?
PDT also covers Los Angeles, San Francisco, Seattle, Vancouver, Portland.
Which countries use PDT, PDT's zone?
PDT is used in United States (Pacific), Canada (British Columbia), Mexico (Baja California).
Is there a day difference between PDT and AST?
Not normally. The +3h gap only pushes the date over for late-evening times.
What is the time difference between PDT and AST?
AST is +3h from PDT.
What timezone is PDT in?
PDT operates on its local timezone.
What timezone is AST in?
AST operates on its local timezone.
Which countries use PDT (Pacific Daylight Time)?
PDT is used in United States (Pacific), Canada (British Columbia), Mexico (Baja California).
Does PDT observe daylight saving time?
Yes, PDT switches to PST during summer months.
What are some interesting facts about PDT?
PDT aligns with MST at UTC-07:00. Tech company earnings calls often reference PDT/PST times.
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 PDT, what time is it in AST?
When it is 12:00 AM (midnight) in PDT (PDT), it is +3h later in AST (AST).
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See every conversion from PDT →·See every conversion from AST →