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Unix Timestamp Converter

Convert Unix epoch ⇄ ISO 8601 ⇄ human time. Shows UTC and local side-by-side.

What this does

Paste any Unix timestamp, ISO 8601 string, or natural date and instantly see every other form: Unix seconds, Unix milliseconds, ISO UTC, full UTC, your local time, and how long ago (or from now) it is.

Seconds vs milliseconds — how the input is detected

  • 10 or fewer digits → treated as seconds (the classic Unix epoch).
  • 12 or more digits → treated as milliseconds (JavaScript / Java conventions).
  • Decimals (1715990400.123) are treated as fractional seconds.

If your timestamp is in microseconds or nanoseconds, divide by 1000 or 1,000,000 first.

ISO 8601 quirks

  • A trailing Z means UTC. No suffix means local time.
  • +05:30 / -04:00 are timezone offsets — handled correctly.
  • Fractional seconds (.123, .123456) are supported.

Common use cases

  • Reading log timestamps from a CSV.
  • Sanity-checking expiration claims in JWTs (exp is Unix seconds).
  • Translating a database created_at for a customer in another timezone.