How to Calculate Time Zone Differences for Remote Meetings
October 8, 2026
Every time zone is defined as an offset from UTC (Coordinated Universal Time) — for example, US Eastern Time is UTC−5 (or UTC−4 during daylight saving). To convert a time between zones, find each zone's current UTC offset and add or subtract the difference.
Skip the math and get your answer instantly:
Open the Time Calculator →Worked Example: Scheduling Across Three Zones
A 10:00 AM meeting in New York (UTC−5, standard time) converts as follows:
| City | UTC Offset | Local Time |
|---|---|---|
| New York | UTC−5 | 10:00 AM |
| London | UTC+0 | 3:00 PM |
| Tokyo | UTC+9 | 12:00 AM (next day) |
Why Daylight Saving Time Breaks Simple Math
Many countries shift their clocks forward or back by an hour for part of the year, but not all do it, and not on the same dates — the US and EU observe daylight saving time but switch on different calendar dates, while much of Asia doesn't observe it at all. This means the offset between two cities can change mid-year, and change by a different amount depending on which zones involved observe DST — a time difference that's 5 hours in January might be 4 or 6 hours in July.
Finding a Meeting Time That Works for Everyone
For recurring meetings across zones, it's more reliable to use scheduling tools that automatically account for each location's current offset (including DST) rather than calculating a fixed difference once and reusing it year-round. A good practice: always specify meeting times with the city or UTC offset attached (e.g., '3:00 PM London / 10:00 AM New York'), not just a bare time, since 'your time' is ambiguous across a distributed team.
The 24-Hour Wraparound
When the time difference pushes a converted time past midnight or before 0:00, the date itself shifts — in the example above, 10:00 AM in New York is already past midnight in Tokyo, making it 12:00 AM the next calendar day. This is a common source of 'what day is the meeting actually on' confusion for widely separated time zones.
Frequently Asked Questions
How do I convert a time from one time zone to another?
Find each zone's current UTC offset, then add or subtract the difference between them. For example, converting from UTC−5 (New York) to UTC+9 (Tokyo) requires adding 14 hours.
Why does the time difference between two cities sometimes change?
Because daylight saving time shifts some zones by an hour for part of the year but not others, and on different calendar dates in different countries — the gap between two cities can be a different number of hours depending on the time of year.
What does UTC mean?
UTC (Coordinated Universal Time) is the global time standard that all time zones are defined relative to, expressed as an offset like UTC+9 or UTC−5 — it doesn't change for daylight saving, making it a stable reference point.
How do I avoid scheduling mistakes across time zones?
Always attach a city name or UTC offset to any meeting time you share, and use scheduling tools that automatically adjust for each participant's current local time (including DST) rather than manually calculating and reusing a fixed offset.
Why does converting to a far time zone sometimes change the date?
When the time difference pushes the converted time past midnight (either forward past 24:00 or backward past 0:00), the calendar date shifts forward or back by one day along with the time, which can cause confusion about which day a meeting actually falls on for each participant.