World Time Difference Calculator

Convert times between cities with clear offsets. Compare dates, overlaps, daylight shifts, and scheduling windows. Plan meetings across regions without confusion or missed hours.

Calculator Inputs

Use the fields below to compare two timezones, estimate meeting end times, and review business-hour overlap.

Reset

Example Data Table

Source City Target City Reference Time Typical Offset Difference Scheduling Note
Karachi London 2026-03-28 14:00 -05:00 Afternoon in Karachi may align with London morning.
New York Dubai 2026-03-28 09:30 +08:00 Early New York meetings can reach Dubai evenings.
Tokyo Los Angeles 2026-03-28 18:00 -16:00 Date changes are common in this comparison.
Sydney Singapore 2026-03-28 10:00 -03:00 Useful for regional sales and support coverage.

Formula Used

Core formula:

Target Time = Source Time + (Target UTC Offset − Source UTC Offset)

The calculator converts the selected source date and time into the source timezone, then applies the target timezone offset at that exact moment. Daylight saving rules are handled automatically by the timezone database, so the offset can change depending on the chosen date.

Working-hour overlap is found by converting both local work windows into absolute timestamps and calculating the shared interval between them.

How to Use This Calculator

  1. Select the reference date and time in the source location.
  2. Choose the source timezone and the target timezone.
  3. Enter the meeting duration in minutes.
  4. Set the working hours for both locations.
  5. Click the calculate button to see the result above the form.
  6. Review the converted time, UTC offsets, date shift, and overlap window.
  7. Use the CSV or PDF buttons to export your report.
  8. Check the Plotly graph to compare hourly conversion across the selected day.

FAQs

1. What does this calculator measure?

It converts a chosen local time from one timezone into another timezone. It also shows UTC offsets, date shifts, meeting end times, and business-hour overlap.

2. Does it handle daylight saving time automatically?

Yes. The calculator uses timezone rules for the selected date, so daylight saving changes are reflected automatically when a location observes them.

3. Why can the target date change?

Some timezone differences cross midnight. When that happens, the target location may show the previous or next calendar day compared with the source location.

4. What is working-hour overlap?

Working-hour overlap is the amount of time when both selected locations are inside their defined business hours at the same moment.

5. Can I use it for global team scheduling?

Yes. It is useful for planning meetings, support coverage, remote work handoffs, webinar timing, and cross-region customer calls.

6. Why does the offset difference show a plus or minus sign?

A positive sign means the target timezone is ahead of the source. A negative sign means the target timezone is behind the source.

7. What does the graph display?

The graph maps each source hour across the selected day to its corresponding target local hour, helping you spot convenient meeting windows quickly.

8. Can I export the result for reporting?

Yes. You can download a CSV report for spreadsheet analysis and a PDF report for sharing, printing, or documentation.

Related Calculators

meeting time zone convertertime zone comparison calculatorconference call time calculatorinternational call scheduler

Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.