Meeting Planner — Time Zone Overlap Finder
Select up to four cities and instantly see where business hours overlap. The Green Zone highlights the window when all participants are within standard working hours.
| City | 00 | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| New York | 20 | 21 | 22 | 23 | 00 | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 |
| London | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 00 |
| Tokyo | 09 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 00 | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 |
Planning Meetings Across Time Zones
Scheduling a meeting that works for everyone is one of the most persistent challenges facing distributed teams. When your colleagues, clients, or partners are spread across continents, what feels like a simple calendar invitation becomes an exercise in temporal arithmetic. A 10 AM call in New York is 3 PM in London, 7:30 PM in Mumbai, and midnight in Tokyo. The further apart the participants are geographically, the harder it becomes to find a slot that does not force someone to work unreasonably early or unreasonably late.
This problem has grown considerably over the past decade. Remote work has expanded the hiring pool from local to global, and companies now routinely operate across five or more time zones. International sales teams coordinate with prospects in different hemispheres. Engineering organizations practice "follow the sun" development, handing off work from one office to the next as the business day migrates westward. In every case, there is an ongoing need to identify the narrow windows during which synchronous communication is practical.
The challenge is compounded by Daylight Saving Time. The United States, most of Europe, and parts of Australia and South America shift their clocks by one hour at different dates throughout the year. During the weeks when one region has changed but another has not, offsets that teams have memorized suddenly become incorrect. A meeting that was scheduled based on "London is five hours ahead of New York" may be wrong for several weeks each spring and autumn when the gap changes to four hours or six hours. Our meeting planner accounts for DST automatically by using the IANA timezone database, so the grid always reflects the true current offset.
Business Hours Convention
The standard most widely used for defining business hours is 9:00 AM to 5:00 PM (09:00 to 17:00) in the local time of each participant. This eight-hour window originated in Western labor practices and has become the default assumption for professional scheduling worldwide. Our tool uses this 9-to-5 convention as the "green" zone for each city.
However, business hours vary meaningfully by country and industry. In Japan, the typical working day runs from 9:00 AM to 6:00 PM or later. In Spain and some Latin American countries, a midday break from 2:00 PM to 5:00 PM can split the workday into two blocks. Financial markets have their own rigid schedules: the New York Stock Exchange operates from 9:30 AM to 4:00 PM Eastern, while the London Stock Exchange runs from 8:00 AM to 4:30 PM GMT. Government offices in the Middle East often observe a Sunday-through-Thursday work week, making Friday and Saturday the weekend rather than Saturday and Sunday.
The "yellow" zones in our grid represent the transition hours from 7:00 AM to 9:00 AM and from 5:00 PM to 7:00 PM. These are periods when a participant can plausibly attend a meeting but may need to arrive early or stay late. Many global teams find that their only viable meeting windows fall in these fringe hours, particularly when bridging Asia and the Americas. Being aware of the yellow zones gives you additional flexibility beyond the strict 9-to-5 overlap.
Finding the Green Zone
The "Green Zone" is the set of UTC hours during which every selected city is simultaneously within standard business hours (9:00 AM to 5:00 PM local time). The calculation works by iterating through each of the 24 hours in a UTC day. For each UTC hour, the tool converts that hour to the local time in every selected city and checks whether the local hour falls within the 9-to-17 range. If all cities pass this check for a given UTC hour, that hour is part of the Green Zone.
When only two nearby cities are selected, the Green Zone can span six to eight hours, giving you ample scheduling flexibility. As you add a third city in a distant time zone, the overlap typically narrows to two or three hours. By the time a fourth city is introduced across the Pacific, the Green Zone may shrink to a single hour or disappear entirely. This visual narrowing is one of the most useful features of the grid: it makes the scheduling constraint immediately obvious rather than requiring manual calculation.
If the tool reports "No overlapping business hours found," it means that at no point in the 24-hour UTC day are all selected cities simultaneously between 9:00 AM and 5:00 PM. This is common when combining cities like New York, London, and Auckland, or Tokyo and Sao Paulo. In these cases, the yellow transition zones become critical. Look for hours where most cities are green and the remaining city is in the yellow zone. A meeting at 7:30 AM local time is not ideal, but it is far better than a 3:00 AM call.
Tips for Global Teams
Rotate meeting times. When there is no perfect window, the fairest approach is to rotate the meeting time so that the inconvenience is shared. If your weekly standup requires someone to join early or late, alternate which region bears that burden from week to week. This prevents resentment and acknowledges that every team member's time is equally valuable.
Default to asynchronous communication. Not every discussion needs to happen in real time. Written updates, recorded video summaries, and collaborative documents allow team members to contribute during their own working hours. Reserve synchronous meetings for decisions that require real-time dialogue, brainstorming sessions, or relationship-building conversations where tone and nuance matter.
Record everything. When meetings do happen across time zones, record them and share the recording with detailed notes. Team members who could not attend at the scheduled time can review the discussion and add their input asynchronously. This practice ensures that no one is excluded from important conversations simply because of geography.
Use UTC as a common reference. When communicating meeting times in emails or messages, always include the UTC time alongside any local time. Saying "Let's meet at 15:00 UTC (11 AM New York, 4 PM London, 8:30 PM Mumbai)" removes ambiguity and reduces the risk of someone converting incorrectly. Our tool displays the Green Zone in UTC precisely for this reason.
Be mindful of cultural norms. In some cultures, scheduling a meeting during the lunch hour or after 5:00 PM is considered inconsiderate. In others, early morning meetings are preferred. When you have the flexibility to choose between two equally valid time slots, pick the one that respects the cultural expectations of the majority of participants.
Frequently Asked Questions
How do I find the best time for a meeting across time zones?
Select 2-4 cities using the dropdown menus in the Meeting Planner above. The visual grid displays a 24-hour timeline for each city with color-coded business hours. The Green Zone, highlighted with a green border, shows the UTC hours during which all selected cities are within standard 9 AM to 5 PM working hours. The best meeting window is also displayed as text below the grid.
What are standard business hours for international meetings?
The widely accepted convention is 9:00 AM to 5:00 PM (09:00-17:00) local time, Monday through Friday. In practice, this varies by country and industry. Japanese business culture often extends to 6:00 PM or later. Some Middle Eastern countries work Sunday through Thursday. Financial markets and government offices keep their own schedules. Our tool uses the 9-to-5 standard as the baseline and marks 7-9 AM and 5-7 PM as transitional periods.
What happens when there is no business hour overlap?
When time zones are too far apart for all participants to be within 9-5 hours simultaneously, the tool displays "No overlapping business hours found." In this case, look at the yellow (transitional) zones on the grid for hours where most cities are green and the rest are only slightly outside business hours. Teams commonly address this by rotating meeting times, using asynchronous communication, or splitting meetings into regional sessions.
Does the meeting planner account for Daylight Saving Time?
Yes. The tool relies on your browser's Intl API and the IANA timezone database, which tracks all DST transitions worldwide. The grid always reflects the current UTC offset for each city, including any active DST adjustment. You do not need to manually account for clock changes.
How many cities can I compare at once?
You can compare between 2 and 4 cities simultaneously. The first two are required, and the third and fourth are optional. With two nearby cities, you will typically see a wide Green Zone. Adding a third city in a distant time zone narrows the overlap. A fourth city may reduce it further or eliminate it entirely, which is useful for understanding the practical limits of synchronous scheduling.
What do the colors in the grid mean?
Green cells indicate standard business hours (9:00 AM to 5:00 PM local time). Yellow cells mark transitional hours (7-9 AM and 5-7 PM) when a participant could join but would be outside the typical workday. Gray cells represent off-hours when scheduling would be unreasonable. Cells with a bright green border are part of the Green Zone, meaning all selected cities are simultaneously in business hours during that UTC hour.