PST vs EST: The Complete Guide to US Pacific and Eastern Time
PST and EST are 3 hours apart — but the gap shifts to 2 hours when daylight saving is in effect for one zone and not the other. Here is exactly what PST and EST mean, when they apply, and how to convert between them.
PST and EST are the two most commonly searched US time zone abbreviations — and also two of the most frequently confused. The short answer: they are normally 3 hours apart, with the East Coast ahead of the West Coast. But that gap can briefly narrow to 2 hours twice a year when the two zones enter or exit daylight saving time on different schedules. Here is everything you need to know.
What Is PST?
PST stands for Pacific Standard Time. It is UTC−8, meaning the clocks run 8 hours behind Coordinated Universal Time. PST is observed by the US West Coast — California, Oregon, Washington, Nevada, and parts of Idaho — as well as the Canadian province of British Columbia. PST is in effect from the first Sunday in November through the second Sunday in March.
During the summer months, those same states switch to Pacific Daylight Time (PDT), which is UTC−7. When people say "PST" casually throughout the year, they often mean Pacific Time in general — both the standard and daylight variants. The IANA identifier for Pacific Time is America/Los_Angeles.
What Is EST?
EST stands for Eastern Standard Time. It is UTC−5, meaning clocks run 5 hours behind UTC. EST covers the US East Coast — New York, Florida, Georgia, Pennsylvania, Ohio, Michigan, and more — plus Ontario and Quebec in Canada. Like PST, EST only applies during the winter months: from the first Sunday in November through the second Sunday in March.
In summer, the East Coast switches to Eastern Daylight Time (EDT), which is UTC−4. The IANA identifier for Eastern Time is America/New_York. When people say "EST" year-round they usually mean Eastern Time broadly, not the specific winter offset.
PST vs EST: Key Differences at a Glance
| PST (Pacific Standard) | EST (Eastern Standard) | |
|---|---|---|
| UTC offset | UTC−8 | UTC−5 |
| Gap between zones | — | 3 hours ahead of PST |
| Active dates | Nov – Mar (approx.) | Nov – Mar (approx.) |
| Summer equivalent | PDT (UTC−7) | EDT (UTC−4) |
| IANA identifier | America/Los_Angeles | America/New_York |
| Major cities | Los Angeles, Seattle, Vancouver | New York, Miami, Toronto |
How to Convert Between PST and EST
The conversion is straightforward when both coasts are on the same type of time (both standard or both daylight):
- PST to EST: add 3 hours. If it is 9:00 AM PST, it is 12:00 PM (noon) EST.
- EST to PST: subtract 3 hours. If it is 3:00 PM EST, it is 12:00 PM PST.
The tricky period is the brief window in spring and fall when one zone has switched to/from daylight saving and the other has not yet. In 2026 for example, the US "springs forward" on March 8. For the two weeks after that date, California is already on PDT (UTC−7) while... wait, the entire contiguous US switches on the same date, so this is rarely an issue domestically. Where it does matter is comparing US Pacific or Eastern time with countries that observe DST on different schedules — like the UK, which switches in late March rather than early March.
PST and EST Business Hours Overlap
With a 3-hour gap, the practical overlap window for business calls between a New York office and a Los Angeles office is roughly 12:00 PM – 6:00 PM EST (9:00 AM – 3:00 PM PST). Early-morning calls that work for New York — like 9 AM EST — land at 6 AM in Los Angeles, before most people start work. Afternoon calls past 3 PM PST land after 6 PM EST, past normal business hours on the East Coast.
Convert any PST ↔ EST time instantly — just enter the time and the date.
PST → EST Converter →PST and EST in Programming
Never hardcode "PST" or "EST" as offsets in application code. Use IANA identifiers instead:
- "America/Los_Angeles" for Pacific Time — automatically switches between PST (UTC−8) and PDT (UTC−7)
- "America/New_York" for Eastern Time — automatically switches between EST (UTC−5) and EDT (UTC−4)
- Store timestamps in UTC; convert to local time only for display
- Never store "9:00 AM PST" as a string — store the UTC equivalent and let the IANA database handle the display
Frequently asked questions
- Is PST always 3 hours behind EST?
- Almost always — but for brief windows in spring and fall when the US and other countries switch daylight saving time on different dates, the gap can temporarily be 2 or 4 hours when comparing with international zones. Within the contiguous US, the 3-hour gap holds year-round because all states switch on the same date.
- What is PDT vs PST?
- PST (Pacific Standard Time) is UTC−8 and applies in winter. PDT (Pacific Daylight Time) is UTC−7 and applies in summer when clocks move forward one hour. The IANA zone "America/Los_Angeles" covers both automatically.
- What US states are on PST?
- California, Oregon, Washington, Nevada, and the northern tip of Idaho observe Pacific Time. Most of those states observe both PST in winter and PDT in summer — though parts of Idaho do not observe DST and stay on Mountain Standard Time year-round.
We build practical, free time and date tools at epochcalc.com — every calculation runs in your browser using IANA tzdb via Luxon, so DST and zone math are correct by construction.