Time Zones & Meetings

Two people describing "3 PM" are not necessarily talking about the same moment, and the offset that converts between them is not fixed year-round in places that observe daylight saving. This category covers converting a specific time between zones, finding a working-hours overlap across a distributed team, planning a meeting that is fair to rotate among time zones, and the daylight-saving edge cases that a naive fixed-offset conversion gets wrong.

An instant and a wall-clock time are different things

"3 PM Tuesday in Chicago" names a specific instant using a local, wall-clock description. Converting it to Tokyo means finding what wall-clock time that same instant is in Tokyo's zone, which requires knowing each zone's actual rules (via its IANA identifier, such asAmerica/Chicago, not a bare UTC offset), because a fixed offset silently breaks the moment either zone crosses a daylight-saving transition.

Some local times are ambiguous, and some do not exist

When clocks fall back, one wall-clock hour happens twice. When they spring forward, one wall-clock hour is skipped entirely and never occurs. A time entered inside either window is flagged rather than silently resolved to a guess, because there genuinely isn't a single correct answer without more information.

Where to go next

For a deadline that needs to be expressed correctly in someone else's local time, see Deadlines & Project Capacity. For a recurring meeting across zones, see Recurrence & Events.

Time Zones & Meetings tools

• Time Zone ConverterConvert a specific local date and time from one IANA zone to another.
• World Meeting PlannerFind an actual meeting slot within the shared availability across participants in different zones.
• Time Zone Difference CalculatorCompare two zones' offsets at a specific instant, since DST can change the difference.
• Working-Hours Overlap CalculatorFind the shared working-hours overlap window across participants in different zones.
• Fair Meeting Rotation PlannerRotate a repeated meeting's inconvenient time slot fairly across time zones.
• Multi-Timezone Event PlannerRender one event's local date and time in as many other zones as needed at once.
• DST Transition ComparatorList every offset transition a time zone makes within a date range.
• Travel Time Zone Shift CalculatorSeparate real elapsed travel time from the clock shift a traveler experiences.
• International Deadline ConverterConvert a deadline across zones, with an explicit same-instant or same-local-time choice.
• Time Zone Availability PlannerScan a date range for the first date offering enough shared availability across zones.
• Follow-the-Sun Handoff PlannerMap the handoff windows between a sequence of regional teams' shifts.
• Remote Team Working Window PlannerSee combined team coverage across a full UTC day and every uncovered gap.
• Time Zone Abbreviation ResolverSee every candidate IANA zone an abbreviation could mean and pick the right one.
• DST Season Meeting PlannerSee how a recurring meeting's remote local time shifts across a DST transition.
• International Date-Line Event PlannerMap one instant to several zones and see when the calendar date itself differs.
• Cross-Zone Business-Day Handoff PlannerFind a real handoff window that requires both locations to be open at once.