Time Zone Meeting Planner

Manual time-zone arithmetic goes wrong for one reason above all others: daylight saving. Offsets are not fixed, the northern and southern hemispheres shift in opposite directions, the changeover dates differ between countries, and places such as India, Japan and most of Africa never change at all. That means the gap between London and New York is five hours for most of the year but four for a few weeks in spring and autumn — which is exactly when recurring meetings quietly break. Reading offsets from a real time-zone database for the specific date removes the guesswork. When no slot works for everyone, rotating which region takes the awkward hour is fairer than permanently burdening one team.

For each of the 24 UTC hours, the local time in every zone is computed from that zone’s offset on the chosen date. An hour is marked as working when every participant falls inside the working day, and as workable when everyone is within two hours of it.

This compares whole hours only and assumes the same working day everywhere, so it will not know about local lunch conventions, part-time schedules, prayer times or public holidays. Zones must be entered as IANA names such as Europe/London rather than abbreviations like EST, which are ambiguous. For dates far in the future, results depend on currently published daylight-saving rules, and governments do occasionally change them.

London, New York and Kolkata share only a narrow window: mid-afternoon in London is late morning in New York and evening in Kolkata, so the workable slots cluster tightly rather than spreading through the day.

1. Enter each participant’s time zone, one per line.
2. Set the date if you are booking more than a few weeks ahead.
3. Adjust the working day if your team starts earlier or later.
4. Pick an hour marked as working for everyone.

• Using ambiguous abbreviations like EST or CST instead of IANA names.
• Assuming the offset between two cities is fixed all year.
• Forgetting that a recurring meeting shifts when only one side changes clocks.
• Always giving the same team the unsociable hour.

The Time Zone Meeting Planner compares up to eight time zones and shows which hours fall inside the working day for everyone. Offsets are read from your browser’s own IANA time-zone database for the date you are planning, so daylight saving is applied correctly rather than assumed.

Distributed teams, freelancers with international clients and anyone scheduling across continents.

• Handles daylight saving for the specific date you are booking.
• Compares up to eight zones at once, not just two.
• Shows near-misses when no hour works perfectly.
• Adjustable working day, since not everyone works 9 to 5.

• Scheduling a recurring standup across three continents.
• Finding a call time with a client in another country.
• Planning a webinar that suits several regions.
• Checking whether a proposed time is unreasonable for someone.