PST to AST: PST is 4 hours behind AST
Pacific Time is 4 hours behind Atlantic Time, on every day of the year. It is 6:04 pm PDT in Pacific and 10:04 pm ADT in Atlantic.
Convert a specific time from PST to AST
Pick any time and date to convert it both ways. The conversion runs in your browser against the real zone rules, so a date inside a daylight saving period gets that period's offset rather than today's.
What is the time difference between PST and AST?
Atlantic Time is 4 hours ahead of Pacific Time. To go from PST to AST you add 4 hours. That gap holds on all 365 days of 2026: both zones move their clocks, but on the same dates and in the same direction, so the distance between them never changes.
PST to AST conversion table
Every hour of Thursday, September 24, 2026 in Pacific, with the matching reading in Atlantic. 4 of the 24 hours land on a different calendar date in Atlantic, which is the part people get wrong when they schedule across this pair.
| PST | PST 24h | AST | AST 24h | Date |
|---|---|---|---|---|
| 12:00 am | 00:00 | 4:00 am | 04:00 | same day |
| 1:00 am | 01:00 | 5:00 am | 05:00 | same day |
| 2:00 am | 02:00 | 6:00 am | 06:00 | same day |
| 3:00 am | 03:00 | 7:00 am | 07:00 | same day |
| 4:00 am | 04:00 | 8:00 am | 08:00 | same day |
| 5:00 am | 05:00 | 9:00 am | 09:00 | same day |
| 6:00 am | 06:00 | 10:00 am | 10:00 | same day |
| 7:00 am | 07:00 | 11:00 am | 11:00 | same day |
| 8:00 am | 08:00 | 12:00 pm | 12:00 | same day |
| 9:00 am | 09:00 | 1:00 pm | 13:00 | same day |
| 10:00 am | 10:00 | 2:00 pm | 14:00 | same day |
| 11:00 am | 11:00 | 3:00 pm | 15:00 | same day |
| 12:00 pm | 12:00 | 4:00 pm | 16:00 | same day |
| 1:00 pm | 13:00 | 5:00 pm | 17:00 | same day |
| 2:00 pm | 14:00 | 6:00 pm | 18:00 | same day |
| 3:00 pm | 15:00 | 7:00 pm | 19:00 | same day |
| 4:00 pm | 16:00 | 8:00 pm | 20:00 | same day |
| 5:00 pm | 17:00 | 9:00 pm | 21:00 | same day |
| 6:00 pm | 18:00 | 10:00 pm | 22:00 | same day |
| 7:00 pm | 19:00 | 11:00 pm | 23:00 | same day |
| 8:00 pm | 20:00 | 12:00 am | 00:00 | the next day |
| 9:00 pm | 21:00 | 1:00 am | 01:00 | the next day |
| 10:00 pm | 22:00 | 2:00 am | 02:00 | the next day |
| 11:00 pm | 23:00 | 3:00 am | 03:00 | the next day |
What are the best hours to schedule a call between PST and AST?
4 hours of the standard 9:00 am to 5:00 pm working day line up in both zones, from 9:00 am PST to 1:00 pm PST. In Atlantic that window reads 1:00 pm to 5:00 pm. Outside it, one side is either not yet at their desk or already gone.
| PST | AST | Working hours | Note |
|---|---|---|---|
| 9:00 am | 1:00 pm | both sides | mid morning in Pacific, afternoon in Atlantic |
| 10:00 am | 2:00 pm | both sides | mid morning in Pacific, afternoon in Atlantic |
| 11:00 am | 3:00 pm | both sides | mid morning in Pacific, afternoon in Atlantic |
| 12:00 pm | 4:00 pm | both sides | noon in Pacific, afternoon in Atlantic |
Does daylight saving change PST to AST?
Pacific Time is currently on PDT and changes next on Sunday, November 1, 2026, when the clock falls back from 1:59 am to 1:00 am and the offset moves from UTC-7 to UTC-8.
Atlantic Time is currently on ADT and changes next on Sunday, November 1, 2026, when the clock falls back from 1:59 am to 1:00 am and the offset moves from UTC-3 to UTC-4.
Is PST ahead of or behind AST?
PST is behind AST by 4 hours: when it is 12:00 pm in Pacific, it is 4:00 pm in Atlantic. One wrinkle worth knowing: PST and PDT are two names for the same zone, not two zones. Pacific Time reads PST in winter and PDT in summer. When somebody types "pst to ast" they nearly always mean the zone rather than the literal winter offset, so this page resolves PST to America/Los_Angeles and AST to America/Halifax and applies whichever offset is genuinely in force on the day.
Pacific Time covers Los Angeles, San Francisco, Seattle and Vancouver. Atlantic Time covers Halifax, Moncton and the Canadian Maritimes. The identifiers behind them are America/Los_Angeles and America/Halifax, which is what any calendar or scheduling system should be storing rather than a fixed number of hours.
Questions
- What is PST in AST?
- PST is 4 hours behind AST. 9:00 am PST is 1:00 pm AST.
- How many hours ahead is AST of PST?
- AST is 4 hours ahead of PST.
- What time is it in Atlantic right now?
- 10:04 pm ADT on Thursday, September 24, 2026.
- When can Pacific and Atlantic meet during working hours?
- Between 9:00 am and 1:00 pm PST, which is 1:00 pm to 5:00 pm AST.
- Does this account for daylight saving?
- Yes. Every reading is computed from the IANA database for the actual date, so PDT and ADT are the abbreviations genuinely in force today rather than a fixed assumption.
Other conversions
12 and 24 hour converter · 8 hours from now · Today · Day counter