Timezone converter

How to convert a time between timezones

1. Pick the source timezone using the dropdown. Your local zone is detected automatically on first load.
2. Pick the target timezone, or use one of the quick-city shortcuts on the side panel.
3. Enter the date and time, or click Now to fill it with the current moment.
4. Read the converted local time in the target zone. The source time is shown below for context.

Common uses

• Scheduling a meeting across two or more cities
• Working out when a webinar, livestream, or product launch happens in your local time
• Coordinating release deadlines with distributed teams, often alongside the Unix timestamp converter for log analysis
• Planning travel arrivals and departures across multiple time zones, with the date calculator for trip durations

For how IANA zones, UTC offsets and daylight saving fit together, see the time tools guide.

Technical specification

• Algorithm or formula: The wall-clock time entered in the source zone is converted to a UTC instant, then re-formatted in the target zone using Intl.DateTimeFormat with the appropriate timeZone option.
• Browser API or library: Native Intl.DateTimeFormat and Intl.supportedValuesOf("timeZone"), both backed by the IANA timezone database bundled with the browser's ICU library.
• Input limits: 400+ IANA zones depending on the browser. Date range follows ECMAScript Date limits (±100,000,000 days from 1970-01-01).
• Output: Converted local time in the target zone, with offset, day-of-week, how far the target zone is ahead of or behind the source zone, and a confirmation of the source time for context.
• Known limitations: Historical DST rules depend on the browser's ICU data version. Some recently changed zones may lag a release behind the upstream tz database.

Frequently asked questions

How does the timezone converter work?

The tool uses Intl.DateTimeFormat with the IANA timezone database that ships in every modern browser. The date and time you enter are treated as wall-clock time in the source zone, then the same absolute moment is formatted in the target zone.

Is the IANA database kept up to date?

The database ships with your browser and updates when the browser updates. A zone whose rules changed very recently may lag a browser release behind the upstream tz database.

How many time zones can I convert between?

Every IANA zone exposed by Intl.supportedValuesOf('timeZone') is available, currently over 400 zones covering every region of the world.

Is my data sent to a server?

All processing runs in your browser. Our servers are not involved at any point.

Does the tool handle daylight saving transitions?

Yes. Conversions for any specific date use the daylight saving rules in effect on that date, including offsets that are not whole hours.