US Six Official Time Zones Conversion Guide
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- Shift Work Calculator — Shift Work Calculator
The Core Conversion Formula
Converting between zones is just offset subtraction.
Formula = Target time = Source time − (source UTC offset − target UTC offset)
Or, more usefully: subtract the difference between the two zones’ UTC offsets. If you’re going from ET (UTC−5) to PT (UTC−8), the difference is 3 hours, so PT time = ET time − 3.
The Six Official US Time Zones
Here’s the full table with standard-time offsets and the major cities in each.
| Zone | Abbrev | UTC offset (standard) | Major cities |
|---|---|---|---|
| Eastern | ET | UTC−5 | New York, Miami, Atlanta, Boston |
| Central | CT | UTC−6 | Chicago, Houston, Dallas, New Orleans |
| Mountain | MT | UTC−7 | Denver, Phoenix*, Albuquerque, Salt Lake City |
| Pacific | PT | UTC−8 | Los Angeles, Seattle, San Francisco, Portland |
| Alaska | AKST | UTC−9 | Anchorage, Fairbanks, Juneau |
| Hawaii-Aleutian | HST | UTC−10 | Honolulu, Hilo |
*Phoenix observes Mountain Standard Time year-round and skips DST.
Step By Step: Converting A Meeting Time
Let’s say a project kickoff is scheduled for 2 PM Eastern, and you need to tell teammates in Chicago, Denver, Phoenix, and Los Angeles what time it is for them.
- Start in ET: 2 PM.
- Chicago (CT, −1 from ET): 2 PM − 1 = 1 PM CT.
- Denver (MT, −2 from ET): 2 PM − 2 = 12 PM MT.
- Phoenix (MT year-round, −2 from ET in winter, −3 during DST): in July 2026 DST is in effect elsewhere, so Phoenix is −3 from ET during summer = 11 AM MST (Phoenix).
- Los Angeles (PT, −3 from ET): 2 PM − 3 = 11 AM PT.
So in July, Phoenix and Los Angeles are on the same clock, even though Phoenix is officially Mountain. That’s the DST wrinkle most people forget.
2026 Real Case: A Conference Call With Honolulu
A coworker of mine scheduled a “10 AM everyone” call for a project spanning New York, Seattle, and Honolulu. She sent the invite with “10 AM” in the subject line and three different local times in the body — but she’d calculated Honolulu as UTC−10 with no DST correction against her own (incorrect) assumption that Seattle would be on standard time in late June. Seattle was on PDT (UTC−7), and Honolulu was on HST (UTC−10), so Honolulu was 3 hours behind Seattle — meaning her 10 AM PT call was 7 AM in Honolulu. Two of the Honolulu team members showed up an hour late because their calendar invite was off. The lesson: when Hawaii is involved, recompute the offset manually, because most calendar tools quietly assume DST applies everywhere.
Conversion Cheat Sheet (Standard Time)
For quick reference, here’s how a single moment — say, 12 PM (noon) Eastern — converts across all six zones during standard time (winter).
| Zone | 12 PM ET equals |
|---|---|
| Eastern | 12 PM |
| Central | 11 AM |
| Mountain | 10 AM |
| Pacific | 9 AM |
| Alaska | 8 AM |
| Hawaii-Aleutian | 7 AM |
During DST (roughly mid-March to early November), every zone except Arizona and Hawaii shifts one hour forward, so the relative offsets stay the same — except Arizona’s offset to other Mountain states, and Hawaii’s to everyone, which both shift by an hour.
DST Boundaries For 2026
The 2026 DST transitions fall on:
| Event | Date 2026 | Effect |
|---|---|---|
| Spring forward | Sun Mar 8, 2026 | 2 AM → 3 AM local; offsets shift +1 |
| Fall back | Sun Nov 1, 2026 | 2 AM → 1 AM local; offsets shift −1 |
Between those dates, all zones except Arizona and Hawaii are on Daylight Time. Outside that window, the standard offsets in the table above apply everywhere.
So what does that mean for you? Recompute any cross-zone schedule twice a year — once in March and once in November. The shift is one hour, but that’s enough to break a recurring meeting or shift handoff.
Tools For Zone Conversion
The US time zone converter handles all six zones with DST built in, so a single timestamp converts correctly regardless of the date. Once you’ve nailed down the local time for each worker, the work hours calculator totals their actual worked hours for the week. And for shift coverage that crosses zones, the shift work calculator lays out the rotation on a single timeline.
For the conceptual background, our how to read US time zones primer covers the offset system from scratch, and our US time zones for remote work guide applies it to distributed teams.
Frequently Asked Questions
What are the six official US time zones?
Eastern, Central, Mountain, Pacific, Alaska, and Hawaii-Aleutian. These cover the 50 states and are defined in federal law at 15 U.S.C. 260. US territories like Guam, Puerto Rico, and American Samoa have separate zones outside the six.
Does every US state observe Daylight Saving Time?
No. Arizona (except the Navajo Nation) and Hawaii do not observe DST, along with several US territories. Everywhere else springs forward in March and falls back in November, shifting the offset between zones by one hour during DST.
What is the offset between Eastern and Pacific Time?
Pacific Time is three hours behind Eastern Time year-round. 9 AM ET is 6 AM PT, and 5 PM ET is 2 PM PT. The offset stays constant because both zones observe DST on the same schedule.
Why does Arizona’s offset to other zones change twice a year?
Arizona stays on Mountain Standard Time year-round while neighboring Mountain states switch to Mountain Daylight Time in summer. That makes Arizona effectively the same as Pacific Time during DST months, then back to Mountain Time in winter.
The Bottom Line
The six US time zones convert with simple offset math, but DST and the Arizona/Hawaii exceptions are where schedulers slip. Run any timestamp through the US time zone converter and you’ll get the right local time in all six zones, with DST handled automatically — no more “is Phoenix on Pacific right now?” guessing.