How to schedule a meeting across time zones

Put every participant's working day on one grid and read the column where they all intersect. The planner does exactly that: add each place, set the hours each person actually works, and the overlapping hours are named for you rather than counted by hand.

Counting in your head is where this goes wrong, because the offset between two places is not one number all year. Two cities that are six hours apart in June can be five apart in late March, so an hour that looks safe today can be outside somebody's day by the time the meeting happens.

Say so, and then decide deliberately. Some sets of places have no hour inside everyone's working day, and pretending otherwise produces a meeting one person attends at midnight without saying anything about it.

Three honest options, in the order worth trying: shorten the meeting so a small stretch outside somebody's day is defensible, split it into two overlapping calls with a written handover between them, or drop the meeting and use a document. A recurring call that only works because one person never sleeps is not a schedule, it is an attrition plan.

So that it cannot be read two ways. Most cross-zone confusion is not an arithmetic error, it is a time written in a form that meant something different to the person reading it.

• Name the place, not just a three-letter abbreviation. IST is India, Israel and Ireland; CST is the American central zone and China. The converter shows what each abbreviation resolves to on a given date.
• Give at least two readings, including one in the time zone of the person least likely to convert it correctly.
• Attach a calendar entry. A real invitation carries the underlying instant, so every guest's client renders it in their own zone and nobody converts anything.
• If a single canonical reading is needed for a written record, use UTC and say UTC.