The short answer
Add the city of every participant to the planner below, pick the date of the meeting and look for columns outlined in green: at those hours everyone is within working hours. If there is no green outline, look for yellow cells, which mark early mornings and evenings that many people can still accept, and choose the column where the fewest people are outside their normal day.
Always plan for a real date, not for today. The difference between two cities can change by an hour in spring and autumn, and a slot that works in January can land at 7:00 for someone in March.
Try it here: Meeting Planner
Open the full tool pageHow time zone overlap works
If two offices both work 9:00 to 17:00, they share 8 minus the time difference in hours. A 1 hour difference (London and Berlin) leaves 7 shared hours, a 5 hour difference (New York and London) leaves 3, and from 8 hours upward (San Francisco and London, New York and Istanbul in winter) there is no shared working hour at all. At that point every option asks someone to start early or stay late.
Half hour and quarter hour zones make the arithmetic less obvious: India is UTC+5:30 and Nepal UTC+5:45, so a meeting at the top of the hour in London starts at half past in Mumbai. Some places also skip daylight saving time entirely, including India, China, Japan, Turkey, most of Africa and Arizona, which means their difference to Europe or North America changes twice a year even though their own clocks never move.
Common city pairs and when they overlap
The table assumes working hours of 9:00 to 17:00 in both cities and uses 24 hour times. January is northern winter, July is northern summer. Check the exact date in the planner, since the switch dates differ between regions.
| City pair | Difference in January | Difference in July | Shared working hours (January) | Practical slot (January) |
|---|---|---|---|---|
| New York and London | 5 h | 5 h | 3 h | 10:00 New York, 15:00 London |
| San Francisco and New York | 3 h | 3 h | 5 h | 10:00 San Francisco, 13:00 New York |
| London and Berlin | 1 h | 1 h | 7 h | Any hour from 9:00 to 16:00 London |
| New York and Berlin | 6 h | 6 h | 2 h | 9:00 New York, 15:00 Berlin |
| London and Istanbul | 3 h | 2 h | 5 h | 10:00 London, 13:00 Istanbul |
| London and Mumbai | 5.5 h | 4.5 h | 2.5 h | 9:30 London, 15:00 Mumbai |
| San Francisco and London | 8 h | 8 h | none | 8:00 San Francisco, 16:00 London |
| New York and Tokyo | 14 h | 13 h | none | 19:00 New York, 9:00 Tokyo next day |
| London and Sydney | 11 h | 9 h | none | 8:00 London, 19:00 Sydney |
Daylight saving time: the weeks that break schedules
The United States and Canada move clocks forward on the second Sunday in March and back on the first Sunday in November. The European Union and the UK switch on the last Sunday in March and the last Sunday in October. For two to three weeks in March and about one week around the end of October, New York is only 4 hours behind London instead of 5, and a recurring 10:00 New York call moves from 15:00 to 14:00 in London.
The southern hemisphere runs the opposite way. Sydney, Melbourne and other parts of southeastern Australia use daylight saving time from the first Sunday in October to the first Sunday in April, so the gap between London and Sydney swings from 9 to 11 hours over the year and passes through 10 hours in between.
Calendar apps adjust recurring meetings automatically, but only relative to the organizer's time zone. A weekly call created in New York keeps 10:00 New York time, and everyone else sees it shift. Tell attendees in advance when this happens, or anchor the series to UTC if your calendar allows it.
Keep it fair when there is no overlap
When a team spans 10 hours or more, someone is always inconvenienced. Do not let it always be the same people, usually those far from headquarters. A few rules that work in practice:
- Rotate the slot: alternate a recurring meeting between an early slot for one region and a late slot for the other, for example every other week.
- Prefer early mornings over late nights: most people accept 8:00 more easily than 21:00, especially with children at home.
- Keep inconvenient meetings short: 30 minutes at 7:30 is acceptable, 90 minutes is not.
- Record the meeting and share notes so attendance outside working hours is optional when possible.
- Avoid Friday afternoon in Europe for calls with Asia and Australia, where it is already Friday evening, and Monday morning in Asia for calls with the Americas, where it is still Sunday.
Write times in the invite so nobody misreads them
Most scheduling mistakes come from the text of the invitation, not from the calendar. Write the time in at least two zones, name cities instead of abbreviations, and include the weekday so date changes are obvious. A line like Tuesday 4 March, 10:00 New York, 15:00 London, 20:30 Mumbai leaves no room for doubt.
Abbreviations are risky: EST is often written in summer when New York is actually on EDT, CST can mean US Central or China Standard Time, and IST is used for India, Ireland and Israel. If you need one reference, add the UTC time. Avoid 12:00 a.m. and 12:00 p.m.; write noon, midnight or a 24 hour time instead.
In the planner, click the hour you chose and press Copy: you get a ready list with the local time, weekday and date for every city, which you can paste straight into the invitation or a chat message.
Common problems and fixes
- Someone joined an hour early or late: the meeting was planned for a date in a different daylight saving period. Re-check the exact date in the planner.
- A colleague's city is missing: time zones are named after a main city, so search the nearest large city or the capital, or type the zone name such as America/Chicago.
- The meeting lands on the wrong day: for very large gaps, an evening call in the Americas is already the next morning in Asia. The planner marks midnight in each row so the date change is visible.
- No hour fits even with yellow cells: widen the working hours in the planner (for example 8 to 18) to see the realistic compromise, or split into two regional meetings.