Remote Cross Time Zone Work Hour Calculation
Try Our Free Calculators
Want to crunch the numbers yourself? Use these free tools:
- US Time Zone Converter — US Time Zone Converter
- Work Hours Calculator — Work Hours Calculator
- Shift Work Calculator — Shift Work Calculator
The Core Formula For Cross-Zone Hours
Cross-zone math is just offset arithmetic plus an overlap check.
Formula = Local hours − offset to reference zone = Reference-zone hours; overlap window = intersection of all members’ converted work blocks
Pick a reference zone (usually Eastern), convert everyone’s local hours into it, then find where all the converted blocks intersect. That intersection is your live collaboration window.
Step By Step: Building A Cross-Zone Overlap Window
Let’s say you have a team of three remote workers, all on a 9 AM–5 PM local schedule:
- Convert each worker’s hours to Eastern Time.
- Ana in New York: 9 AM–5 PM ET (offset 0).
- Ben in Chicago (Central, −1): 10 AM–6 PM ET.
- Carla in Los Angeles (Pacific, −3): 12 PM–8 PM ET.
- Find the overlap: the latest start to the earliest end. Latest start is 12 PM (Carla), earliest end is 5 PM (Ana). Overlap = 12 PM–5 PM ET, a 5-hour window.
That 5-hour window is the only block where all three are clocked in. Schedule anything outside it and someone’s off the clock — or being asked to work outside their normal hours.
2026 Real Case: A Distributed Sales Team’s Standup
A friend of mine runs a sales team with reps in Boston, Austin, and San Diego. For months she held a 9 AM ET standup that worked for Boston, was 8 AM for Austin (fine), and was 6 AM for San Diego (miserable). Attendance from the San Diego rep was consistently bad, and she’d quietly assumed he was slacking. Once she ran the overlap math, she moved the standup to 11 AM ET — 10 AM in Austin, 8 AM in San Diego — and his attendance jumped. Same meeting, different hour, completely different outcome. The math took five minutes; the assumption took three months of frustration.
The Six US Time Zones And Their Offsets
Here are the official US time zones with their standard-time offsets from UTC and from Eastern.
| Zone | Abbrev | UTC offset (standard) | Offset from ET |
|---|---|---|---|
| Eastern | ET | UTC−5 | 0 |
| Central | CT | UTC−6 | −1 |
| Mountain | MT | UTC−7 | −2 |
| Mountain (Arizona) | MT | UTC−7 | −2 (no DST) |
| Pacific | PT | UTC−8 | −3 |
| Alaska | AKT | UTC−9 | −4 |
| Hawaii-Aleutian | HST | UTC−10 | −5 (no DST) |
Arizona and Hawaii skip DST, which means their offset relative to other zones changes twice a year. That’s a recurring trap for any team with members in Phoenix or Honolulu.
Overlap Windows For Common Team Spreads
The wider your team’s geographic spread, the smaller the overlap window — sometimes to zero.
| Team spread | Common local hours | Overlap in ET |
|---|---|---|
| ET + CT | 9–5 local | 10 AM–5 PM (7 hrs) |
| ET + CT + MT | 9–5 local | 11 AM–5 PM (6 hrs) |
| ET + CT + PT | 9–5 local | 12 PM–5 PM (5 hrs) |
| ET + PT + Hawaii | 9–5 local | 2 PM–5 PM (3 hrs) |
| ET + AK + HST | 9–5 local | 2 PM–5 PM (3 hrs, DST-dependent) |
So where do people mess this up? They schedule against the company’s headquarters clock and assume everyone’s “9 to 5” means the same wall-clock hours. It doesn’t. Convert first, schedule second.
Tools For Cross-Zone Scheduling
The US time zone converter translates any local time across all six zones, including DST. Once you’ve pinned the overlap window, the work hours calculator totals each team member’s actual worked hours for the week. And for shift-based coverage across zones, the shift work calculator handles rotation and overlap side by side.
For deeper context, our US time zones for remote work guide covers the team-scheduling side, and our how to read US time zones primer walks through the offset system from scratch.
Frequently Asked Questions
How do you calculate work hours across US time zones?
Pick a reference time zone, convert every team member’s local hours into that reference using the offset, then find the overlap window where all members are clocked in. Always confirm whether DST is in effect, since offsets shift twice a year.
Which US time zone is best as a reference for remote teams?
Eastern Time is the most common reference because it covers the largest share of the US workforce and aligns with financial markets. For teams weighted toward the West Coast, Pacific Time is sometimes used, but ET remains the default for payroll and meeting scheduling.
Does overtime get calculated in the worker’s local time or the company’s time?
In the worker’s local time. FLSA overtime is based on hours actually worked in the employee’s workweek, regardless of where the employer is headquartered. A remote worker in California hits the California daily overtime thresholds by California clock, not Eastern.
How does DST affect cross-time-zone work hour math?
Daylight Saving Time shifts the offset between zones by one hour for part of the year. Arizona and Hawaii do not observe DST, so their offset relative to other states changes in spring and fall. Recompute overlap windows whenever DST starts or ends.
The Bottom Line
Cross-time-zone work hour math is offset conversion plus overlap intersection — with a DST caveat baked in for Arizona and Hawaii. Convert everyone to one reference zone, find the intersection, and pay overtime based on the worker’s local clock, not the company’s. Run your team’s hours through the US time zone converter and the overlap window reveals itself instead of staying hidden in someone’s calendar frustration.