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Unix Timestamp Converter

Convert Unix timestamps to dates and back, in any IANA time zone.

Written by Golam Rabbani, Founder & Lead Engineer

Auto-detects seconds vs milliseconds.

How to use this unix timestamp converter

  1. Pick the conversion direction — timestamp to date, or date to timestamp.
  2. Paste a Unix timestamp (seconds or milliseconds) or pick a date and time.
  3. Choose the IANA time zone you want the human-readable output in.
  4. Press Convert to see ISO 8601, a formatted local string, and the raw epoch value.
  5. Use Copy to grab any field, or Reset to start over.

About this unix timestamp converter

A Unix timestamp is the number of seconds (or milliseconds) that have elapsed since 1970-01-01 00:00:00 UTC, the so-called Unix epoch. Almost every backend system stores timestamps this way because the value is timezone-agnostic, monotonic, and trivial to compare. The converter lets you flip a timestamp into a human-readable date — or a date back into a timestamp — without firing up a REPL.

The tool autodetects whether your input is in seconds (10 digits) or milliseconds (13 digits) and renders the result against the IANA zone you choose, using the browser's native Intl.DateTimeFormat to honour the local DST rules for that zone. We assume valid IANA zones such as `America/New_York` or `Asia/Tokyo`; the offset shown reflects DST for the specific instant, not a fixed offset.

For example, the timestamp `1717977600` becomes `2024-06-10T00:00:00Z` in UTC, `2024-06-09T20:00:00-04:00` in `America/New_York`, and `2024-06-10T09:00:00+09:00` in `Asia/Tokyo`. Use it to debug API responses, build log filters, or verify that a backend cron actually fired when you think it did.

FAQ

What is a Unix timestamp?
It is the number of seconds since 1970-01-01 00:00:00 UTC, ignoring leap seconds. It is the standard way most databases, log files, and APIs represent a point in time.
Seconds or milliseconds — how does the tool know?
It looks at the length of the number. A 10-digit value is treated as seconds; a 13-digit value as milliseconds. You can also paste either and the formatted output will match.
Does the converter handle daylight saving time?
Yes. It uses Intl.DateTimeFormat with the IANA zone you choose, so the offset shown reflects DST in force at the specific instant rather than a fixed offset.
Can it go past the year 2038 problem?
Yes. JavaScript numbers are 64-bit doubles, so the tool handles timestamps far beyond the 32-bit signed-int limit that legacy C systems hit in 2038.
Does the tool send my data anywhere?
No. The entire conversion runs in your browser. Nothing is logged, uploaded, or stored between sessions.