Time Zone Converter

Guide: Time Zone Converter

How the conversion works

Every moment has one absolute time, UTC. A time zone is a rule that adds an offset to UTC, and daylight saving changes that offset on certain dates. To convert, the tool first turns the wall-clock time you typed into a UTC instant, then shows that instant in each city.

The formula

• Local time = UTC + offset, where the offset (for example +9:00 for Tokyo, −5:00 for New York in winter) comes from the zone’s rules on that date.
• UTC = wall time − offset. Because the offset itself depends on the date, the tool checks it twice around daylight-saving switches.

Example: 12:00 in New York on 15 January is 17:00 UTC, which is 02:00 the next day in Tokyo (+9). In July New York is at −4, so the same noon is 16:00 UTC.

Using the meeting planner

Each row is a city and each column is one hour of your chosen date. The number in a cell is that city’s local hour. Green cells fall in 9:00–18:00, amber in the early morning or evening (7–9 and 18–22) and grey at night. The outlined column is your chosen time. The note under the grid lists every hour where all cities are inside working hours; when there is none, pick a shoulder hour and rotate who takes the inconvenient slot.

Tip: two weeks a year, countries switch to daylight saving on different dates, so recheck meetings in March, late October and early November.

FAQ

Does it handle daylight saving time?

Yes. It uses your browser’s built-in IANA time zone database through the Intl API, so offsets are correct for the exact date you choose, including past and future dates.

How do I find a meeting time for several cities?

Add every city, set the date, and read the planner rows. Green cells are 9:00–18:00 local time; the note below lists hours when all cities are in working hours.

What does "Time is in" mean?

It is the zone of the date and time you typed. Everything else is converted from it.

Why does a city show a different date?

Zones far east or west of each other can be on different calendar days at the same instant. The date column shows each city’s own date.

Is my location used?

Only your device’s time zone name, read locally, to pre-select your city. Nothing is sent anywhere.