PST to EST: time zone conversion

To convert PST to EST, add 3 hours: 09:00 PST is 12:00 EST. It’s 3 hours in summer too, when 09:00 PDT is 12:00 EDT, because both zones switch to daylight saving on the same days: in 2026, March 8 and November 1.

A worked conversion

The tool below starts at 09:00 in Los Angeles on Thursday, January 15, 2026:

2026-01-15 09:00 America/Los_Angeles (UTC-08:00, PST)
2026-01-15 12:00 America/New_York (UTC-05:00, EST)

When the date changes

From 21:00 Pacific on, it’s already tomorrow in New York. That matters for deadlines: “11:59 PM PT on January 15” is 02:59 EST on January 16, so an East Coast team gets nearly three extra hours, while an 11:59 PM ET deadline closes at 8:59 PM in California. Say which zone a deadline is in, every time.

The changeover nights

Each coast changes at 02:00 local time, three hours apart, and for those three hours the gap is off by one. On March 8, between 07:00 and 10:00 UTC, Los Angeles is still on PST while New York is on EDT: 4 hours apart. On November 1, between 06:00 and 09:00 UTC, Los Angeles is still on PDT while New York is on EST: 2 hours apart.

Abbreviation traps

PST is only the winter name. From March 8 to November 1, 2026, Los Angeles, Seattle and Vancouver are on PDT, UTC−7, and New York is on EDT. “PT” and “ET” are safe to write all year. Code is less forgiving: Python’s ZoneInfo("PST") raises ZoneInfoNotFoundError, and GNU date treats an unknown TZ=PST as UTC with the label PST. Use America/Los_Angeles and America/New_York.

In code

from datetime import datetime
from zoneinfo import ZoneInfo

datetime(2026, 1, 15, 9, 0, tzinfo=ZoneInfo("America/Los_Angeles")).astimezone(ZoneInfo("America/New_York")).isoformat()
# '2026-01-15T12:00:00-05:00'

TZ=America/New_York date -d 'TZ="America/Los_Angeles" 2026-01-15 09:00'    # GNU date
# Thu Jan 15 12:00:00 EST 2026

new Date('2026-01-15T17:00:00Z').toLocaleString('en-US', { timeZone: 'America/New_York', timeZoneName: 'short' })
// '1/15/2026, 12:00:00 PM EST'

Meeting window

A 09:00–17:00 day on each coast overlaps from 09:00 to 14:00 Pacific, which is 12:00 to 17:00 Eastern: five hours. The end of the Pacific day, 17:00, is already 20:00 in New York.