Time Zone Converter
Convert any time between any two time zones with automatic DST handling. Pin a live world clock for the cities you work with. Everything runs in your browser.
Intl.DateTimeFormat. Daylight-saving transitions are handled automatically from the historical timezone rules. No data is sent to any server.
World Clock
Updated every secondFinding This Time Zone Converter Useful?
Get the standalone version — a single HTML file you can keep on your machine and open anytime, fully offline.
Get the Standalone VersionWhat Is a Time Zone Converter?
A Time Zone Converter takes a date and time in one time zone and shows what that same moment is in another. It answers questions like "if it is 3 PM in New York, what time is it in Berlin?" or "what time should I suggest for a call that works for Tokyo and London?". This tool uses the browser's built-in IANA timezone database, which includes the full history of DST rules, so transitions and offset changes are handled automatically. It also shows live clocks for the zones you care about, and it works entirely offline.
Key Features
400+ IANA Time Zones
Every time zone in the IANA database, from UTC and America/New_York to obscure zones like Pacific/Chatham and Asia/Kathmandu.
Automatic DST Handling
Daylight saving transitions are applied based on the historical rules for each zone. No manual adjustment needed.
Live World Clock
Pin any number of time zones and watch their current time update every second, with day labels for yesterday/today/tomorrow.
One-Click Swap
Reverse the conversion direction and adjust the wall-clock time to match — so the moment stays the same but the labels flip.
Search by City or ID
Type a city name, country, or IANA identifier to filter the zone list instantly.
Nothing Leaves Your Browser
Time zone data comes from the browser. No API calls, no analytics, no server. Works offline.
How to Use the Time Zone Converter
- Choose Now or Specific time — Now converts the current moment; Specific lets you pick a date and time.
- Pick a source time zone — use the search box to filter, or type an IANA ID directly.
- Pick a target time zone — the same way. Use the swap button to reverse.
- Click Convert — the result updates automatically as you change any field.
- Read the result — the converted time is shown in large type, with the offset, abbreviation and both sides of the comparison.
- Add zones to the world clock — pin the cities you work with and watch their live times update.
Practical Use Cases
Scheduling Meetings
Find a time that works for colleagues in different time zones without guessing.
Travel Planning
Check what time it will be at your destination when you land.
Remote Work
Know when your teammates are online before sending a message or scheduling a call.
Event Planning
Publish times for webinars, launches or streamed events in multiple zones.
Trading & Markets
Convert market open and close times between exchanges in different zones.
Customer Support
Check the local time for a customer before replying to a support ticket.
Important Notes and Limitations
A few honest caveats:
• The IANA database is updated a few times a year. Governments occasionally change DST rules or even permanent offsets. Your browser updates the database as part of its own releases, so what you see matches the browser's knowledge, which may lag the latest rule change by a few weeks.
• Historical times before 1970 may be approximate. The IANA database has the best available data, but pre-1970 records for some zones are incomplete or disputed, especially for regions that changed time zone rules before international standards existed.
• Future dates can shift. If a government announces a DST rule change for a future date and the browser has not yet been updated, the conversion will use the old rule.
• Some very small time zones may not appear. The list includes the full IANA database, which covers all inhabited land areas, but tiny offshore territories or historical zones might use a parent zone instead.
• For legal or contractual purposes, always verify. If you are scheduling something with real consequences — a contract deadline, a court hearing, a flight — cross-check with an authoritative source. This tool is a convenience, not a legal reference.
Frequently Asked Questions
Yes. The browser's IANA timezone database contains the full history of DST rules for every zone. When you convert a date and time, the tool looks up the correct offset for that specific date in that specific zone, so a January conversion in New York uses EST and a July conversion uses EDT automatically. No manual adjustment needed.
The IANA database uses geographic identifiers in the form "Region/City" — for example "America/New_York", "Europe/London", or "Asia/Kolkata". Some cities have historically been renamed (for example, "Asia/Calcutta" was renamed to "Asia/Kolkata") and both names may still be present as aliases. The tool displays the canonical name plus any alias, so you may see your city listed under both the current and historical identifier.
No. The tool relies entirely on the browser's built-in Intl.DateTimeFormat API and the IANA database that ships with your browser. There are no API calls, no analytics, and no server involved. You can use the tool with the network tab open and see zero outgoing requests. The standalone edition works completely offline.
It matches whatever version of the IANA database your browser ships with. Chrome, Firefox, Safari and Edge all update this database regularly, typically within a few weeks of an official change being published. If a government recently announced a DST change and your browser has not yet been updated, the tool will use the older rule until the browser refreshes its database. For the vast majority of conversions, the data is accurate.
Yes. The IANA database goes back to the 19th century for most zones, though the accuracy of older entries varies. For dates before 1970, some zones have incomplete or disputed records — especially for regions that changed their offset multiple times before international standards were formalised. For legal or archival work involving historical dates, cross-check with an authoritative source.
Yes. The zones you add to the World Clock are stored in your browser's localStorage under a single key, so they persist across page reloads on the same browser and device. They are never sent to any server. Clearing your browser data or using a private window will reset them.
About the Author — GenieDevs
Get the Standalone Version
Time Zone Converter — Standalone Edition
One self-contained HTML file with the full converter and world clock inside. Keep it on your machine, run it from a USB stick, or use it on an air-gapped computer — no internet connection needed.
Final Takeaway
Coordinating across time zones is one of those small frictions that never fully goes away — but it does not have to be error-prone. This converter gives you the exact time in any zone, handles DST for you, and lets you pin a live clock for the cities you deal with most. Because it runs entirely in your browser using the IANA database, it works offline, it is fast, and nothing you type is ever sent anywhere.