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Unix Timestamp Converter

Convert Unix timestamps (epoch seconds or milliseconds) to human-readable dates, or back. Live UTC + local time, ISO 8601, all timezones.

  • Runs in browser
  • No signup
  • No tracking
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How to use Unix Timestamp Converter

  1. Paste a timestamp — the tool auto-detects seconds vs milliseconds.

  2. Switch the timezone selector to see the date in another zone.

  3. Or use the date picker to compose a date and read its epoch value.

  4. Copy the converted value with one click.

When to use it

  • Decoding JWT exp / iat / nbf claims.

  • Reading server logs that timestamp in epoch seconds.

  • Building cron expressions or scheduled jobs.

  • Debugging time-based bugs across timezones.

What it fixes

  • Confusing seconds with milliseconds — leading to dates 50,000 years in the future.

  • Forgetting that Unix timestamps are UTC, not local time.

  • Doing date math in your head and getting it wrong.

About Unix Timestamp Converter

A Unix timestamp counts seconds since the Unix epoch (1970-01-01 UTC). It's the backbone of timekeeping across databases, log files, JWT exp claims, cron schedules, and HTTP headers.

This converter handles both seconds (10-digit) and milliseconds (13-digit) inputs, renders the result in UTC, your local timezone, and ISO 8601, and lets you compose a date in any timezone to derive its epoch value.

References: MDN — Date.prototype.getTime() · Wikipedia — Unix time

Frequently asked

  • What is a Unix timestamp?

    Number of seconds (or milliseconds) elapsed since 1970-01-01T00:00:00Z, ignoring leap seconds. The de facto standard for storing time in databases and APIs.

  • Seconds or milliseconds?

    Unix tradition uses seconds. JavaScript's Date.now() and most modern APIs use milliseconds. Heuristic: 10 digits = seconds, 13 digits = milliseconds.

  • Why does my timestamp show a different time than expected?

    Unix timestamps are timezone-agnostic — always UTC. Display values depend on the timezone you pick. Switch the timezone selector to verify.

  • Is this private?

    Yes. Conversion runs entirely in your browser via the JavaScript Date object — no network calls.

Discussion

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