Calculator Form
Example Data Table
| Example Base Time | Source | Target 1 | Target 2 | Target 3 | Work Window | Meeting Duration |
|---|---|---|---|---|---|---|
| 2026-03-28 09:30 | Asia/Karachi | Europe/London | America/New_York | Asia/Tokyo | 09:00 to 17:00 | 1.50 hours |
| 2026-06-12 14:00 | Asia/Dubai | Europe/Berlin | America/Chicago | Australia/Sydney | 08:30 to 18:00 | 1.00 hour |
| 2026-11-05 18:15 | Asia/Singapore | Europe/Paris | America/Los_Angeles | Pacific/Auckland | 10:00 to 19:00 | 2.00 hours |
Formula Used
Target Local Time = Source Local Time − Source UTC Offset + Target UTC Offset
Difference from Source = Target UTC Offset − Source UTC Offset
Overlap Start = max(All Workday Starts in UTC)
Overlap End = min(All Workday Ends in UTC)
Meeting Fits = Yes, when Overlap Duration ≥ Meeting Duration
The calculator uses timezone-aware date objects, so daylight saving changes are applied automatically for the selected instant.
How to Use This Calculator
- Choose the base date and time for your starting location.
- Select the source time zone.
- Select up to three comparison time zones.
- Enter your normal workday start and end time.
- Enter the meeting duration you want to schedule.
- Click Compare Time Zones.
- Review converted times, offsets, date shifts, overlap, and meeting feasibility.
- Use the CSV or PDF buttons to export the result.
Frequently Asked Questions
1) What does this calculator compare?
It compares one source time zone against three target time zones. It shows local time, UTC offset, date shift, working-hour status, and whether a shared meeting window exists.
2) Does it handle daylight saving time?
Yes. The conversion uses timezone-aware rules for the exact date and time entered. That means seasonal offset changes are applied automatically where they exist.
3) Why do some locations show the previous or next day?
Large timezone differences can move a converted time across midnight. The calculator highlights this with previous-day, same-day, or next-day labels so scheduling mistakes are easier to avoid.
4) What is the shared work window?
It is the common overlap between all selected local work windows after converting them into UTC. This shows when every location is available at the same time.
5) Can I use overnight work windows?
Yes. If the workday end time is earlier than the start time, the calculator treats it as an overnight shift and extends the interval into the next day.
6) Why are some timezone differences not whole hours?
Some regions use half-hour or quarter-hour offsets. The calculator keeps decimal hour differences so the comparison stays accurate for those locations.
7) What does meeting feasibility mean?
It checks whether the shared overlap duration is at least as long as your requested meeting duration. If not, the selected work window cannot support that meeting.
8) Can I export the results?
Yes. After calculation, you can download the comparison table as CSV or PDF for planning, documentation, and team coordination.