Enter two people’s UTC offset and typical working hours to find the best overlapping window for a call or meeting.
This tool converts each person’s working-hours window into UTC, finds the overlap between the two UTC windows, and converts that overlap back into each person’s local time.
Person 1
UTC offset (e.g. -5 for US Eastern):
Working hours: to
Person 2
UTC offset:
Working hours: to
How It Works
This tool converts each person’s working-hours window into UTC, finds the overlap between the two UTC windows, and converts that overlap back into each person’s local time.
How to Use This Tool
- Enter Person 1’s UTC offset (for example, US Eastern Standard Time is -5).
- Enter Person 1’s typical working hours.
- Do the same for Person 2.
- Click Find Overlap to see the best meeting window in UTC and in each person’s local time.
UTC offsets shift with daylight saving time in many places; double-check the current offset for each location before relying on this for scheduling.
The Math Behind It
To compare two people, the tool first puts both schedules on the same clock. UTC time = local time − UTC offset. Then it keeps only the hours that fall inside both people’s windows.
Worked example: Person 1 is on US Eastern Standard Time (UTC−5) and works 9 to 17. In UTC, that is 14:00 to 22:00. Person 2 is in a place at UTC+1 and also works 9 to 17, which is 8:00 to 16:00 in UTC. The two windows overlap from 14:00 to 16:00 UTC. Converted back, that is 9:00 to 11:00 for Person 1 and 15:00 to 17:00 for Person 2. Two hours of shared time is enough for a focused meeting, but not for a full day of collaboration.
Choosing a Meeting Time Within the Overlap
- Avoid the edges: The first and last part of a workday are often the busiest or least focused, so aim for the middle of the overlap when you can.
- Check both calendars: The overlap only tells you when both people could be working, not when they are free.
- Watch for daylight saving changes: Two locations can switch on different dates, which temporarily changes the overlap.
- Share the time in both zones: Send the invitation with both local times written out so nobody has to convert.
Did You Know?
- UTC (Coordinated Universal Time) does not observe daylight saving time, which is exactly why it is used as a stable reference point for scheduling across time zones.
- Some countries, like India and Iran, use time zone offsets with a 30- or 45-minute component instead of a full hour.
Frequently Asked Questions
What if there is no overlap at all?
The tool will let you know there is no overlap given the offsets and hours entered; one side may need to adjust its working hours for an occasional early or late call.
Does this account for daylight saving time automatically?
No, you need to enter the current UTC offset for each location, which may change twice a year in places that observe daylight saving time.
Can I use different working hours for each person?
Yes. Each person has their own start and end hours, so you can enter a late-start schedule, an early shift, or a shortened day, and the tool will find where they overlap.
What if I am scheduling more than two people?
Run the tool for one pair at a time, then compare the windows. A simple approach is to find the overlap for the two people furthest apart, since any time that works for them will usually work for people in between.
How do I enter a location with a half-hour offset?
Use a decimal. India is 5.5 and Nepal is 5.75, for example.