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Timestamp Converter

Convert between Unix epoch (s / ms), ISO 8601, RFC 2822, and your local time.

 

What this tool does

Convert a timestamp between Unix epoch (seconds or milliseconds), ISO 8601 / RFC 3339, RFC 2822, and a human-readable date in your timezone — all in one place. Paste whatever you have; the tool detects the format and shows the equivalent in every other one. No server calls.

How to use it

Paste a timestamp in any common format, or click Now to start from the current instant. The detected format is shown below the input; the equivalent in every other format appears in the grid.

Detected examples:

  • 1700000000 — Unix seconds (10 digits)
  • 1700000000000 — Unix milliseconds (13 digits)
  • 2024-07-04T14:23:00Z — ISO 8601 / RFC 3339
  • Wed, 02 Oct 2002 13:00:00 GMT — RFC 2822

Limits and edge cases

  • Digits-only input is interpreted as epoch. 10 digits → seconds, 13 digits → milliseconds. Other lengths are best-effort.
  • The displayed timezone is your browser’s. ISO 8601 (local) and Human readable both reflect that. ISO 8601 (UTC) and the two Unix forms are timezone-independent.
  • Times are accurate to the millisecond (a JavaScript Datelimit). For nanosecond timestamps from databases or tracing systems, you’ll lose precision — trim the trailing digits first.
  • Relative time (“3 hours ago”) is computed against the current instant at render — it doesn’t auto-refresh.

Frequently asked questions

Is anything sent to a server?
No. Parsing and formatting happen entirely in your browser via the Date and Intl APIs.
Why are 10-digit numbers seconds and 13-digit numbers milliseconds?
By convention. A Unix timestamp in seconds is 10 digits from 2001 through ~2286; the same instant in milliseconds is 13 digits. Inputs with 11 or 12 digits are ambiguous — the tool guesses milliseconds but flags it.
What timezone is the output in?
Your browser's. Unix epoch and ISO 8601 (UTC) are timezone-independent; ISO 8601 (local) and Human readable use the timezone shown next to the detected-format badge.
Can it parse 'July 4 2024' or other natural strings?
Yes — anything `Date.parse` understands works. The detected-format badge will say 'other' to signal that the format isn't a documented standard.
Does it handle Unix timestamps before 1970?
Yes. Negative epoch values represent dates before 1970-01-01 UTC and work correctly.