US Time Zones Explained: EST, CST, MST, PST and UTC

Every US time zone conversion is a fixed offset — one, two or three hours between the four mainland zones. The only thing that ever complicates it is daylight saving, and even that moves everything together.

ConversionBy Aug 29, 20266 min read
US Time Zones Explained: EST, CST, MST, PST and UTC — ListCalc

The four zones and their UTC offsets

The mainland United States runs on four time zones. Each is defined as a fixed offset from Coordinated Universal Time (UTC), and each shifts one hour forward during daylight saving.

ZoneStandard (winter)Daylight (summer)
Eastern (ET)EST — UTC−5EDT — UTC−4
Central (CT)CST — UTC−6CDT — UTC−5
Mountain (MT)MST — UTC−7MDT — UTC−6
Pacific (PT)PST — UTC−8PDT — UTC−7

Because all four zones switch on the same dates, the gaps between them never change: Central is always one hour behind Eastern, Mountain two hours behind, Pacific three hours behind. That is why CST to EST is always +1 hour and EST to PST is always −3, in January and in July alike.

Eastern = Central + 1 hour
Eastern = Mountain + 2 hours
Eastern = Pacific + 3 hours

The same moment in all four zones

EasternCentralMountainPacific
9:00 AM8:00 AM7:00 AM6:00 AM
12:00 PM11:00 AM10:00 AM9:00 AM
3:00 PM2:00 PM1:00 PM12:00 PM
6:00 PM5:00 PM4:00 PM3:00 PM
9:00 PM8:00 PM7:00 PM6:00 PM

Read it in either direction: a 9:00 AM Pacific stand-up is a noon meeting for New York (PST to EST), and a 3:00 PM Eastern deadline lands at 1:00 PM in Denver (EST to MST). The pairs people convert most often each have a dedicated tool: CST to PST, PST to CST and MST to EST.

Daylight saving: the only moving part

In 2026, US daylight saving time begins at 2:00 AM on Sunday, March 8 (clocks jump to 3:00 AM) and ends at 2:00 AM on Sunday, November 1 (clocks fall back to 1:00 AM). Between those dates the whole country’s labels change — EST becomes EDT, CST becomes CDT, and so on — but the gaps between US zones stay identical.

What does change is the offset to anywhere that doesn’t observe DST. Converting Eastern time to UTC means adding 5 hours in winter but only 4 in summer, because UTC never shifts.

The famous exception is Arizona, which stays on Mountain Standard Time all year (the Navajo Nation within Arizona does observe DST). In practical terms: in winter Phoenix matches Denver, and in summer Phoenix matches Los Angeles.

Converting to India (IST)

India Standard Time is UTC+5:30 — a half-hour offset, and no daylight saving. That makes IST to EST one of the few conversions where the gap itself changes twice a year:

SeasonDifferenceExample
US winter (EST)IST is 10½ h ahead8:00 PM IST = 9:30 AM EST
US summer (EDT)IST is 9½ h ahead8:00 PM IST = 10:30 AM EDT

Military time in ten seconds

The 24-hour clock removes AM/PM ambiguity entirely: hours run 00 to 23. From 1:00 PM onward, add 12 to the hour; before 1:00 PM, the numbers match (midnight is 0000).

12-hour24-hour
12:00 AM (midnight)0000
6:00 AM0600
12:00 PM (noon)1200
1:00 PM1300
5:30 PM1730
9:00 PM2100
11:59 PM2359

The military time converter handles both directions, and the general time zone converter covers any pair of zones worldwide, DST included.

Run your own numbers

CST to EST EST to PST PST to EST CST to PST PST to CST MST to EST EST to MST EST to UTC IST to EST Military time

FAQ

What is the time difference between EST and PST?
Three hours. Pacific time is always three hours behind Eastern — 12:00 PM in New York is 9:00 AM in Los Angeles. The gap is the same in winter (EST/PST) and summer (EDT/PDT) because both zones change on the same daylight saving dates.
Is CST one hour behind EST?
Yes. Central time is exactly one hour behind Eastern year-round, so 3:00 PM EST is 2:00 PM CST. To go the other way, add one hour — 2:00 PM CST is 3:00 PM EST.
Why does the EST to UTC offset change during the year?
UTC never observes daylight saving, but US Eastern time does. In winter, Eastern is UTC−5; from March to November it runs as EDT at UTC−4. So converting Eastern to UTC means adding 5 hours in winter but only 4 in summer.
Does Arizona change its clocks?
Most of Arizona does not — it stays on Mountain Standard Time (UTC−7) all year. The Navajo Nation within Arizona is the exception and does observe daylight saving. As a result, Phoenix matches Denver in winter and Los Angeles in summer.
How far ahead is India of US Eastern time?
India Standard Time is UTC+5:30 with no daylight saving, so it is 10½ hours ahead of EST in the US winter and 9½ hours ahead of EDT in the US summer.

Sources

Primary references used for the figures and rules on this page.

  1. Daylight Saving Time rules — NIST / time.gov
  2. US time zone boundaries — US Department of Transportation