US Time Zone Converter - ET, CT, MT, PT with DST
zone ↔ zoneConvert times between US time zones (Eastern, Central, Mountain, Pacific, Alaska, Hawaii) with automatic daylight saving time handling.
US Exclusive Use Cases
This converter covers the four mainland US time zones plus Alaska and Hawaii, built for American cross-zone work:
- Remote-work meeting scheduling: finding overlapping working hours across US coasts
- Cross-border business calls: aligning US East Coast and West Coast meeting times
- Overseas study coordination: syncing US class times with international students
- US stock-market hours: converting NYSE ET open/close into your local US zone
US vs Global Calculation Differences
The converter is anchored to the US mainland zone structure and DST rules:
- Four mainland zones: Eastern, Central, Mountain, Pacific, the core US business grid
- US DST rule: "spring forward, fall back" on the second Sunday of March and first Sunday of November, distinct from EU dates
- Arizona exception: most of Arizona does not observe DST, a US-specific quirk
- Hawaii no-DST: Hawaii stays on standard time year-round, unlike most US zones
Common Calculation Mistakes
Common mistakes: forgetting the US DST switch dates (March and November, different from Europe), assuming a fixed hour offset year-round, ignoring that Arizona and Hawaii do not observe DST, and double-counting the DST hour on transition days. Always confirm whether the target date is in standard or daylight time.
Tool Algorithm & Precision Explanation
The converter uses IANA time-zone identifiers so DST is handled automatically:
- IANA zones: America/New_York, America/Chicago, America/Denver, America/Los_Angeles, America/Anchorage, America/Honolulu
- Automatic DST: the browser computes the correct offset for the selected date, including transition days
- Difference output: shows the signed hour difference between the two selected zones
- No manual offset entry: eliminates off-by-one errors from hard-coded UTC offsets
US Federal Holiday & Workday Reference
US time-zone offsets and DST status for the mainland zones:
| US Zone | Standard Offset | Daylight Offset | DST? |
|---|---|---|---|
| Eastern (ET) | UTC-5 | UTC-4 | Yes |
| Central (CT) | UTC-6 | UTC-5 | Yes |
| Mountain (MT) | UTC-7 | UTC-6 | Yes (most) |
| Pacific (PT) | UTC-8 | UTC-7 | Yes |
| Alaska (AKT) | UTC-9 | UTC-8 | Yes |
| Hawaii (HST) | UTC-10 | UTC-10 | No |
Frequently Asked Questions
When does US daylight saving time start and end?
US DST starts on the second Sunday of March (spring forward) and ends on the first Sunday of November (fall back). This differs from the EU schedule.
How do I schedule a meeting across US coasts without errors?
Select the Eastern zone and your time, then choose Pacific as the target. The converter accounts for current DST so both coasts stay aligned.
Does Arizona observe daylight saving time?
Most of Arizona stays on Mountain Standard Time year-round and does not observe DST, except the Navajo Nation. The converter uses America/Denver which follows DST.
Why does my time difference change in March and November?
Because the US DST switch dates shift each zone by one hour. The converter recomputes the offset for the actual date so the difference updates automatically.
What is the time difference between Eastern and Pacific?
Pacific is 3 hours behind Eastern year-round during DST, and also 3 hours during standard time, since both zones shift together on the same US dates.
Does Hawaii observe daylight saving time?
No. Hawaii stays on Hawaii Standard Time (UTC-10) all year with no DST, so its offset to the mainland changes in March and November.