UTC
12:00 AM
Thu, Jan 1, 2026
America/New_York
-1 day07:00 PM
Wed, Dec 31, 2025
Europe/London
12:00 AM
Thu, Jan 1, 2026
The IANA Time Zone Database (also called the tz database or Olson database) is the authoritative registry of world time zones maintained by ICANN. It tracks every historical and current UTC offset, daylight saving schedule, and political boundary change for 500+ zones. Scheduling a meeting across time zones without accounting for DST boundaries is one of the most common sources of international scheduling errors.
The converter uses JavaScript's Intl.DateTimeFormat API to format a given Date object according to a target IANA time zone identifier. When you set a source date and time, the tool creates a JavaScript Date representing that moment in your selected source zone, then re-formats the same instant using each target zone's Intl settings.
DST handling is automatic: the browser's built-in IANA database knows the exact transition dates and times for every zone, so a conversion from US/Eastern on March 8 correctly shows the post-spring-forward time while March 7 shows the pre-change time.
The working hours overlay compares the converted hour in each target zone against the configurable working window (default 9 AM–6 PM) and shades the result green or grey accordingly — giving a visual overlap scan without needing to inspect each number individually.
A remote team lead in IST scheduling a weekly sync that works for teammates in New York (EST), London (GMT), and Sydney (AEST) without an overlap that falls outside 9–6 for any participant.
A SaaS startup scheduling a product launch announcement to go live at 9 AM Pacific Time and verifying what time that is in Europe and India before setting the release.
A freelance developer in Bangalore converting a client's stated deadline of "Friday 5 PM EST" to IST to know when their actual cutoff is.
An event organizer confirming that a webinar at 3 PM CET does not fall in the middle of the night for attendees in Singapore (SGT) or São Paulo (BRT).
Scope note: The converter relies on the IANA timezone database bundled with your browser, which may lag by 1–2 months behind legislative changes for rarely-observed zones. For mission-critical scheduling in countries that change DST rules annually (e.g., Iran, Morocco), verify against the official government announcement.
Select your source time zone and enter the date/time
Add target time zones using the + button
See the converted time, date, and UTC offset instantly
Use the working hours indicator to find overlap
Copy all results with one click
Task trackers, project planners, and automation scripts that save hours every week. Starting at $4.
Browse Productivity Kits