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Timezone difference

Select two timezones to compare their current UTC offset and local time.

How Timezone difference works

Timezone Difference shows the current UTC offset gap between any two IANA timezone identifiers and tells you what time it is right now in each location. It uses the browser's built-in Intl.DateTimeFormat API, which automatically applies DST rules for the current date, so the displayed offset reflects the actual current difference rather than a nominal standard offset that may be wrong during summer time. Nothing you select is sent to a server.

IANA timezone names (such as America/New_York, Europe/Paris or Asia/Tokyo) are more precise than abbreviations like EST or CET, because abbreviations are ambiguous and do not encode DST transitions. The tool accepts full IANA identifiers and derives the correct UTC offset for today's date on the fly. This means if one city is in summer time and the other is not, the tool shows the real-world offset in effect right now.

Written by Bastien Sulyan

How to use Timezone difference, step by step

  1. Select or type the first IANA timezone in the left field.
  2. Select or type the second IANA timezone in the right field.
  3. Read the current local time displayed for each timezone.
  4. Note the offset difference shown between the two locations.
  5. Change either timezone to compare a different pair.

Common use cases

  • A project manager scheduling a cross-continental call checks the real-time offset between New York and London to find a slot that falls within business hours in both cities.
  • A developer debugging a distributed system checks the offset between their local timezone and the server's UTC timezone to interpret log timestamps correctly.
  • A freelancer working with a client overseas checks the current offset before sending a meeting invitation to avoid scheduling at an inconvenient hour for the client.
  • A traveller comparing flight arrival times in their home timezone versus the destination timezone uses the tool to quickly read both local times simultaneously.

Frequently asked questions

Why does the tool use IANA timezone names instead of abbreviations like EST or GMT+1?

Timezone abbreviations are ambiguous: EST refers to different offsets depending on whether you mean US Eastern Standard Time or Australian Eastern Standard Time. IANA identifiers like America/New_York uniquely identify the timezone and include the correct DST transition rules. The browser's Intl API uses IANA identifiers internally.

Does the displayed offset account for daylight saving time?

Yes. The offset is computed for the current date using the Intl API, which applies the DST rules for each timezone as defined in the IANA database. If one location is in summer time and the other is not, that asymmetry is reflected in the offset shown.

Can I check the offset for a future or past date rather than right now?

The current tool shows the offset as of the present moment. To check what the offset will be on a specific future date (useful around DST transitions in March and October), you would need to temporarily change your system date, or consult a timezone database that supports historical and future queries.

Does selecting a timezone send my choice to an external server or analytics service?

No. The timezone offset calculation is performed entirely by the browser's Intl API using locally installed data. Your timezone selections are not transmitted anywhere.

What if the timezone I need is not in the list?

The tool lists all IANA timezone identifiers supported by the browser's Intl implementation. This covers several hundred named zones. If a very recent IANA update added a new zone not yet in the browser's data, it may be absent; updating your browser or OS usually resolves this.

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