Timezone Converter
Convert a date/time between 23 IANA timezones with DST-correct UTC offsets at the converted moment.
Tool code processes selected files and entered content in your browser and does not submit them to a TOOLGRID processing endpoint. TOOLGRID measures tool usage, not the content you enter.
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Browser-basedWhat this tool does
In-browser timezone converter using the IANA zone database. Handles DST automatically; accepts wall-clock or ISO-with-offset input.
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.
What you can do with this tool
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.
What to check before relying on the result
- Performance and maximum practical input size depend on browser memory, device speed, and the structure of the input.
- Review the generated result before replacing or publishing an original file.
How to use
- 1
Type a date/time in the input — wall-clock format like 2026-05-16T15:30, or leave empty for the current moment.
- 2
Pick the source timezone from the dropdown — this is the zone the input is interpreted in.
- 3
Pick the target timezone. The converted time appears below with both ISO and human-readable formats, plus UTC offsets on each side.
Use Cases
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.
Tips & Tricks
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.
On a spring-forward day, 02:30 may not exist; the converter rejects that wall-clock input instead of silently moving it to another time. On a fall-back day, 01:30 can occur twice, so check the displayed UTC offset against the occurrence you intended.
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.
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
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?
The browser's Intl.DateTimeFormat API performs the conversion using the IANA timezone database that ships with the browser engine. Tool code does not submit entered values to a TOOLGRID processing endpoint.
What happens for non-existent or ambiguous local times around DST?
A non-existent spring-forward wall-clock time fails closed and must be corrected before conversion. A duplicated fall-back time can represent two moments; check the displayed UTC offset and use an ISO string with an explicit offset when the occurrence must be unambiguous.
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.
Useful next steps
Open a nearby browser tool when you need to validate, convert, or reuse the result.