Timezone converter

A time zone converter takes one moment and shows it in several places at once. Pick a date and time, choose the zone it’s in, and the tool lists the matching local time in every zone you add, including your own by default.

How does it handle daylight saving time?

Automatically. Rather than applying a fixed UTC offset per zone, the tool asks the browser’s built-in Intl API what a given zone’s offset actually is at that specific instant, which already accounts for whether daylight saving is in effect on that date. That means a meeting in Berlin in July and one in January land on the correct UTC offset without you having to remember which one applies, and it also handles the rarer edge case of a time that falls in the hour skipped when clocks jump forward for DST, resolving it to the nearest real instant instead of erroring out.

Where do the time zone rules come from?

From the IANA time zone database, the reference dataset that tracks every zone’s current and historical offset and DST rules, and that essentially every browser and operating system ships and updates on its own. The tool doesn’t maintain its own copy of this data; it reads it through Intl.DateTimeFormat, so the zone list and its rules stay current as long as your browser does.

Does the time I enter get sent anywhere?

No. Everything runs in your browser using the Intl API that’s already built into it, so no date, time, or zone you enter is sent to a server. That matters if the time you’re converting comes from a private calendar invite, an internal deployment schedule, or anything else you’d rather not paste into a random web form.

What is this useful for?

Common uses: scheduling a call across offices in different countries, checking when a release window opens in your local time, or working out what time a flight lands after crossing zones. See MDN’s guide to Intl.DateTimeFormat for more on the API behind the conversions, and the IANA time zone database for background on how zone rules are tracked.