Timezone Converter
Convert a date / time between 23 named IANA zones, with DST and exact UTC offsets at the converted moment.
Pourquoi utiliser cet outil
05Free in-browser timezone converter. Pick source and target zones from a curated list of IANA names (UTC, New York, London, Tokyo, Shanghai, Sydney, and more), enter a wall-clock date/time in the source zone, and get the converted time in the target zone plus the exact UTC offsets at that moment. Daylight-saving rules are respected automatically.
Enter a date/time, pick the source and target timezones, and the converter shows the equivalent moment in the target zone — plus the exact UTC offset on each side (which can differ from the nominal offset around DST transitions).
Leave the input empty to use the current moment. Wall-clock input like 2026-05-16T15:30 is interpreted in the source zone. ISO strings with an explicit offset (...Z or ...+02:00) are honored as-is regardless of the source-zone setting.
Useful for: scheduling cross-region meetings, debugging logs that span timezones, sanity-checking server outputs that report UTC, converting historical timestamps where DST rules differ from today, or planning travel across hemispheres.
All computation uses the browser's Intl.DateTimeFormat against the IANA timezone database that ships with your browser. No upload, no server lookup, no third-party API. Pair with our Timestamp Converter when you need to round-trip through Unix epoch values.
Comment l'utiliser
03Vérifications rapides avant de copier
03Confirmez que le format de saisie est celui attendu.
Vérifiez le résultat avant de l'utiliser dans un document, une URL, une config ou un message.
Copiez uniquement le résultat dont vous avez besoin.
Cas d'utilisation
Pick the meeting time in your local zone, convert to the other party's zone, and confirm there's no overlap with their out-of-hours. Faster than counting offsets in your head.
Server logs typically report UTC. Convert the moment of interest into your local time to align with what you were doing then, or into the customer's local time to understand their context.
Around DST shifts, the same wall-clock hour can map to two different UTC moments (or none). The converter shows the actual offset at the entered moment so you can confirm which side of the transition you're on.
Take an outbound departure (in your local zone) and a flight duration, calculate the UTC arrival, then convert to the destination zone for the local arrival time.
If two systems disagree on what timestamp <code>1747401000</code> represents, convert both displays into a common zone (UTC works best) and the discrepancy usually shows up as one system using seconds and the other milliseconds.
Conseils et astuces
- 01Wall-clock input vs ISO-with-offset
Bare local strings (<code>2026-05-16T15:30</code>) are interpreted in the source zone. ISO strings with <code>Z</code> or <code>+HH:MM</code> are treated as absolute moments and the source-zone dropdown is irrelevant for them. Pick whichever input form matches what you actually have.
- 02DST creates non-existent and ambiguous local times
On a spring-forward day, 02:30 may not exist. On a fall-back day, 01:30 happens twice. The converter resolves these by picking the first valid moment — but be aware they exist and check the displayed UTC offset matches what you expected.
- 03Offsets aren't fixed per region
America/New_York is UTC-5 in winter and UTC-4 in summer. America/Phoenix is UTC-7 year-round (no DST). Asia/Shanghai is UTC+8 year-round. The exact offset is computed for the moment you entered, not a generic value.
- 04IANA zone names beat city/abbreviation names
EST means different things in different contexts (Eastern Standard Time has fixed UTC-5; Eastern Time follows DST). IANA names like America/New_York unambiguously include the DST rules — that's what this tool uses internally and what most modern code should use.
FAQ
07
Does the converter handle daylight saving time?
Yes — DST is handled automatically because the converter uses IANA timezone names (e.g., America/New_York instead of EST). The UTC offset for a given moment is computed for that exact moment, so the result reflects whichever side of the DST shift you're on.
How many timezones are supported?
The dropdown lists 23 commonly-used IANA zones covering all major regions. Browsers ship with the full IANA database (~600 zones) so adding any specific zone is trivial — open an issue or message us with the zone you'd like included.
What does the UTC offset readout show?
The exact offset at the converted moment, in the form UTC±HH:MM. This can differ from the zone's nominal offset across DST transitions and historical edge cases. Two offset readouts (source and target) appear so you can see both sides, plus a 'Difference' card showing how far the two zones are apart at that moment.
Can I paste a Unix timestamp directly?
Not in this tool's input — it expects a date/time string. For Unix-epoch conversion, use our Timestamp Converter which accepts seconds, milliseconds, and ISO 8601 strings directly. The two tools are designed to be used together.
Is the conversion sent to a server?
No. The browser's Intl.DateTimeFormat API performs the conversion locally using the IANA timezone database that ships with the browser engine. No network calls, no third-party API, no logging.
What happens for non-existent or ambiguous local times around DST?
On the spring-forward day, the missing hour (e.g., 02:00 to 03:00 in many US zones) is resolved by skipping forward — entering 02:30 actually evaluates as if you meant 03:30 in the post-shift zone. On fall-back days, the duplicated hour resolves to its first occurrence. Always check the displayed UTC offset matches what you expected.
Why is my ISO input ignored when the source zone changes?
ISO strings with an explicit offset (suffix like Z or +05:00) are absolute moments — they don't need a source zone to interpret. The converter trusts the offset in the string. To re-interpret an ISO string in a different source zone, strip the offset suffix before pasting.
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