This tool visualizes working hours across multiple time zones on a 24-hour UTC timeline. It calculates the overlap where all selected time zones are within their working hours (default 9 AM–5 PM local time). The green segments show optimal meeting times for global teams, taking daylight saving time (DST) into account for the selected date.

Yes! The tool uses the IANA time zone database through your browser's Intl.DateTimeFormat API. When you change the date, it automatically recalculates each time zone's UTC offset, accounting for DST transitions. This is critical for accurate scheduling across regions with different DST rules (e.g., US vs EU vs Australia).

For teams spanning the US (Eastern), Europe (London/Berlin), and Asia (Singapore/Tokyo), the typical overlap is narrow—often between 7:00–9:00 AM ET (12:00–14:00 UTC), which is early afternoon in Europe and late evening in Asia. This tool helps you find and visualize that golden window. Consider rotating meeting times to share the inconvenience fairly.

The current version applies the same working hours to all time zones for simplicity. You can adjust the global Work Start and Work End times (e.g., 8:00–18:00 for flexible schedules). For per-person customization, consider using separate instances of the tool or noting individual availability separately.

UTC (Coordinated Universal Time) serves as a neutral reference point unaffected by time zones or DST. By mapping all local work hours onto a UTC timeline, the tool can precisely calculate overlaps without ambiguity. This is the standard method used by global scheduling platforms like Google Calendar and World Time Buddy.

There is no hard limit—you can add as many time zones as you need. However, with more than 6–8 time zones spanning the globe, the overlapping window may become very small or nonexistent. The tool will clearly indicate when no overlap exists, helping you plan staggered or rotating meeting schedules instead.