Toolivaro

Free Meeting Overlap Planner

Find the time windows when teams in different time zones can meet, using their local work hours and DST-aware math.

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Zones and work hours (local)

How is the result calculated?

Warsaw, New York, and Tokyo on one date

Warsaw works 09:00–17:00 (UTC+2), New York 09:00–17:00 (UTC−4), Tokyo 09:00–18:00 (UTC+9). Warsaw’s window is 07:00–15:00 UTC, New York’s is 13:00–21:00 UTC, Tokyo’s is 00:00–09:00 UTC. The only common minute is 13:00–15:00 UTC — two hours, shown as 15:00–17:00 in Warsaw, 09:00–11:00 in New York, and 22:00–24:00 in Tokyo. That is the window to book.

Input Value
date 2026-08-04
windows Warsaw 09–17, New York 09–17, Tokyo 09–18
Result 13:00–15:00 UTC (2 h) · Warsaw 15:00–17:00 · New York 09:00–11:00 · Tokyo 22:00–24:00

What is the formula and its assumptions?

Work window in UTC

window(zone) = [startHour, endHour) local, converted per minute

Symbol Meaning
[start, end) start hour included, end hour excluded
converted per minute every minute is evaluated in local wall time

Per-minute evaluation makes DST transitions within the day exact — no fixed-offset assumption.

Overlap

overlap = ⋂ window(zone) for all zones

Symbol Meaning
⋂ intersection: minutes inside every window

What are the most common mistakes?

  • Assuming a zone’s offset is fixed — a one-hour DST shift quietly breaks meetings planned with fixed offsets.
  • Planning only for the overlap of the start hours, ignoring that the end hour of one zone may cut the window short.
  • Forgetting that "09:00–17:00" is local to each zone, not a shared time.

What are the assumptions and limitations?

  • Plans a single date per run; recurring patterns must be checked per date.
  • Windows are whole-hour by design in version 1; half-hour work days are not supported.
  • The planner finds windows in work hours — it does not check personal calendars.

Where do the numbers come from?

Last reviewed August 4, 2026 · Version 1.0.0 · Toolivaro does not guarantee external content.

Time Time Zone Converter Convert any date and time between IANA time zones with correct daylight-saving handling and explicit offsets. Time Business Days Calculator Count business days between dates or add business days to a date — weekends and your own holidays excluded. Time Date Difference Calculator Calculate the exact number of days, weeks, months, and years between two dates — with a single trusted method.

Frequently asked questions

How are DST transitions handled?

Every minute of the day is converted in each zone’s local wall time, so a zone that changes offset mid-day produces a window that genuinely shifts — the planner never assumes a fixed offset. This matters most in the weeks around the spring and autumn transitions.

What if there is no overlap?

The planner says so explicitly instead of proposing an impossible time. In practice, teams then widen one zone’s window or shift hours — the honest answer is more useful than a fabricated one.

Can I plan for several days at once?

Version 1 plans one date at a time. For a recurring cadence, check the boundary dates around the next DST change — that is where a fixed weekly slot usually breaks.

Found a mistake or have a correction? Report it — we review every correction.