Timezone Overlap Calculator
Find overlapping working hours between time zones. Compare 2 or 3 time zones and find the best meeting time for remote teams.
Overlapping Hours
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Overlap in Timezone 1 —
Overlap in Timezone 2 —
Extended More scenarios, charts & detailed breakdown ▾
Overlap Hours
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Overlap in TZ1 —
Overlap in TZ2 —
Professional Full parameters & maximum detail ▾
Overlap Summary
Raw Overlap Hours —
Net Overlap (excl. lunch) —
Local Times
Overlap Window in TZ1 —
Overlap Window in TZ2 —
Suggested Meeting (UTC) —
How to Use This Calculator
- Enter the UTC offset for each time zone (e.g., −5 for US Eastern, +9 for Tokyo).
- Set work hours start and end for each team (default 9 AM to 5 PM).
- See overlapping hours and the overlap window in each local time.
- Use Three Timezones tab to find a 3-way meeting window.
- The Professional tier adds lunch break exclusion and timezone presets.
Formula
UTC Start 1 = Work Start 1 − UTC Offset 1
UTC Start 2 = Work Start 2 − UTC Offset 2
Overlap Start = max(UTC Start 1, UTC Start 2) • Overlap End = min(UTC End 1, UTC End 2)
Overlap Hours = max(0, Overlap End − Overlap Start)
Example
Example: New York (UTC-5, 9–17) and London (UTC+0, 9–17). UTC windows: NY = 14:00–22:00, London = 9:00–17:00. Overlap: 14:00–17:00 UTC = 3 hours. In NY: 9 AM–12 PM. In London: 2 PM–5 PM.
Frequently Asked Questions
- The calculator converts each team's work hours to UTC using their UTC offset, then finds the intersection of those UTC windows. The overlapping range is displayed in each team's local time.
- If the UTC working windows do not intersect, the result shows 0 hours of overlap. You may need to adjust one team's flexible hours or find a time outside normal business hours.
- Use the "Three Timezones" tab. Enter all three UTC offsets and working hours. The calculator finds the intersection of all three windows and suggests the optimal meeting slot.
- This calculator uses fixed UTC offsets. For DST-aware calculations, manually adjust the offset for the relevant period (e.g., US Eastern changes from UTC-5 to UTC-4 during summer).
- US Eastern: UTC-5 (winter) / UTC-4 (summer). US Pacific: UTC-8 / UTC-7. London: UTC+0 / UTC+1. Berlin: UTC+1 / UTC+2. Mumbai: UTC+5.5. Tokyo: UTC+9. Sydney: UTC+10 / UTC+11.