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Timestamp Converter

A Timestamp Converter translates between Unix epoch seconds or milliseconds, ISO 8601 strings, and human-readable date/time representations in any time zone, performed entirely client-side using the browser's Intl and Date APIs.

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About Timestamp Converter

Enter a Unix timestamp (seconds or milliseconds) or a date string and see all common representations side-by-side: ISO 8601 UTC, ISO 8601 with offset, RFC 2822, Unix seconds, Unix milliseconds, and a long-form localized date. We auto-detect whether your input is in seconds or milliseconds.

What Timestamp Converter does

  • Auto-detects seconds vs milliseconds based on input magnitude
  • Side-by-side ISO 8601 UTC, ISO 8601 with offset, and RFC 2822 outputs
  • Local time zone plus any IANA time zone you pick
  • Quick presets (now, start of day, start of month)
  • Built on Intl + Date APIs — no library round-trip

When to reach for Timestamp Converter

  • Decoding a Unix timestamp out of a log line
  • Generating an ISO 8601 string for an API request body
  • Translating a UTC timestamp into the user's actual local time
  • Spotting timezone bugs when an event fires at the wrong wall-clock time

How to use Timestamp Converter

  1. 01

    Paste a timestamp or date

    Enter a Unix timestamp (seconds or milliseconds) or a date string in any standard format.

  2. 02

    Pick a time zone

    Default is your local zone; pick any IANA zone (e.g. Asia/Tokyo) from the selector.

  3. 03

    Copy the format you need

    Each representation (Unix s, Unix ms, ISO 8601, RFC 2822, long-form local) has its own copy button.

When to use Timestamp Converter vs alternatives

AlternativeUse Timestamp Converter when…Use the alternative when…
`date -d @<ts>` in the terminalyou want every representation visible at once with timezone picker.you are scripting and need a single format.
epochconverter.comthe timestamp is from production traffic or contains user identifiers you would rather not paste into a third-party service.you specifically want a feature offered there that we do not have.

Frequently asked questions

Is the timestamp in seconds or milliseconds?
Unix timestamps are traditionally in seconds. JavaScript's Date.now() returns milliseconds. We auto-detect based on magnitude: 10-digit numbers are read as seconds, 13-digit as milliseconds.
Does this account for time zones?
Yes. The converter shows both the UTC and your local time zone interpretation. You can also pick a specific time zone using the IANA name list.
What is ISO 8601?
ISO 8601 is the international standard date format. The most common variant is 'YYYY-MM-DDTHH:mm:ss.sssZ' — used by virtually every modern API.