Time Zones: How to Schedule an International Meeting Without Mistakes
A colleague in London, a client in Singapore, a team in Los Angeles: working across borders has become routine. Finding a meeting time that works for everyone is much less so. Between time differences, clocks that don't change on the same day, and attendees who end up on the previous or next day, mistakes are common. Here's a simple method to schedule without getting it wrong, with the help of our time zone converter.
The basics: UTC and offsets
Every time zone is defined relative to a single worldwide reference: Coordinated Universal Time (UTC). New York is at UTC−5 in winter and UTC−4 in summer; London at UTC+0 in winter and UTC+1 in summer; Tokyo at UTC+9 all year round.
To convert a time from one zone to another, go through UTC: subtract the offset of the starting zone, then add the offset of the destination zone. For example, 3 PM in London on January 15 (UTC+0) is 15:00 UTC, which is 10 AM in New York (UTC−5).
Not all offsets are whole hours: India is at UTC+5:30, Nepal at UTC+5:45, and parts of Australia at UTC+9:30. And a single country can have several: the contiguous United States has four main time zones and Russia has eleven, while China, despite its size, runs on a single official time.
The daylight saving time trap
Clock changes are the main source of mistakes, for three reasons.
Countries don't change their clocks on the same day
The United States and Canada spring forward on the second Sunday in March and fall back on the first Sunday in November. The United Kingdom and the European Union switch on the last Sunday in March and the last Sunday in October. As a result, for a few weeks each spring and fall, the gap between New York and London is 4 hours instead of 5. A weekly meeting set for "10 AM New York, 3 PM London" suddenly falls at 2 PM for the attendees in London.
Seasons are reversed in the Southern Hemisphere
When North America and Europe move to summer time, southeastern Australia, New Zealand and Chile go back to standard time. The gap between New York and Sydney therefore varies between 14 and 16 hours over the course of the year.
Many places don't change their clocks at all
Japan, China, India, most of Africa and South America, as well as Hawaii and most of Arizona, stay on the same time all year. With them, the gap changes twice a year, purely because of our own clock changes.
Method: finding a common time slot
- List the attendees and their cities, not just their countries: Vancouver and Toronto aren't on the same time.
- Define an acceptable window for each person, for example 8 AM to 7 PM local time.
- Convert those windows into a single time zone (yours or UTC) to find where they overlap.
- Check on the actual date of the meeting, not today's date, to account for clock changes.
- Share the inconvenience if no slot suits everyone: early morning for some one time, late evening for others the next.
A few reference points from New York (Eastern Time):
| With… | Comfortable slot (Eastern Time) |
|---|---|
| Toronto, Miami, Atlanta | The whole working day (same time) |
| Los Angeles, Vancouver | Noon to 5 PM (9 AM to 2 PM for them) |
| London, Dublin, Lisbon | 9 AM to noon (afternoon for them) |
| Paris, Berlin, Madrid | 8 to 11 AM (afternoon for them) |
| Dubai, India | 7 to 8:30 AM (late afternoon or evening for them) |
| Tokyo, Singapore, Sydney | About 6 to 9 PM (the next morning for them) |
Bringing together the US West Coast, Europe and Asia at the same time during office hours is nearly impossible: in that case, it's often better to hold two sessions, or to rely on written updates.
Writing a clear invitation
- Always state the time zone: "3 PM (London time)" or "15:00 UTC", never just "3 PM".
- Add the local time for the main attendees: "10 AM New York / 3 PM London / 11 PM Singapore" (in winter). That saves everyone from doing the math again.
- Flag the change of day: a meeting at 7 PM on Monday in New York takes place at 9 AM on Tuesday in Tokyo.
- Use a calendar invitation: digital calendars automatically adjust the time for each recipient. Just make sure the event's time zone is set correctly.
- Beware of abbreviations: "CST" can mean US Central Standard Time or China Standard Time, and "IST" can mean India, Ireland or Israel. Use a city name or the UTC offset instead.
Beyond work
The same puzzle comes up when calling a relative abroad without waking them, watching a soccer match or a Formula 1 race live on the other side of the world, working out the local arrival time of a long-haul flight, or joining an online product launch. In every case, the right habit is the same: convert on the exact date of the event.
Converting a time in seconds
Our time zone converter does the math for you:
- your time zone is detected automatically;
- enter the time and date to convert, then choose the destination city;
- the result shows the local time, the full date, a "Previous day" or "Next day" label if the day changes, as well as the time difference and the UTC offset;
- the "Swap" button converts in the other direction.
The tool relies on the official time zone database (IANA) built into your browser: each country's daylight saving rules are applied for the date you enter, including non-whole-hour offsets.
In short
To never miss an international meeting again: think in cities rather than countries, check the time on the exact date of the event, watch out for the weeks around clock changes, and always state the time zone in your invitations. With these few habits and a reliable converter, time differences become a simple formality.