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Unix timestamp converter

Unix timestamp converter is a time tool that translates between Unix epoch timestamps and human-readable dates. It auto-detects seconds versus milliseconds, displays UTC, local, and relative time, and provides a live current-timestamp button. The tool runs in your browser.

Enter a value above to convert

MODE

Runs entirely in your browser

How to convert a Unix timestamp

  1. Paste a Unix timestamp (seconds or milliseconds) into the input field.
  2. The tool converts it to a human-readable date and time instantly.
  3. Toggle between UTC and your local time zone.
  4. Or enter a date and time to get the corresponding Unix timestamp.

Common uses

  • Debugging API responses that contain Unix timestamps, use JWT decoder to inspect the exp and iat claims in auth tokens
  • Converting timestamps in server logs to readable dates
  • Getting the Unix timestamp for a specific date to use in a query or script. The date calculator is useful for adding or subtracting days from a date

Technical specification

  • Algorithm or formula: Constructs a JavaScript Date from the timestamp via new Date(value) (milliseconds) or new Date(value * 1000) (seconds). Reverse direction uses date.getTime() divided by 1000 for seconds output.
  • Browser API or library: Native Date and Intl.DateTimeFormat for locale-aware formatting; no external library.
  • Input limits: 10-digit values are treated as seconds (valid through year 2286), 13-digit values as milliseconds. Range follows ECMAScript Date limits (±100,000,000 days from 1970-01-01).
  • Output: UTC ISO string, local time formatted for your zone, and a human-readable relative time (e.g., "3 days ago"). Bidirectional: date-to-timestamp also supported.
  • Known limitations: Leap seconds are not represented (matches JavaScript Date semantics). Sub-second precision beyond milliseconds is not modeled.

Frequently asked questions

What is a Unix timestamp?
A Unix timestamp is the number of seconds (or milliseconds) elapsed since 1 January 1970 00:00:00 UTC (the Unix epoch). It is a standard way to represent dates in programming.
How do I know if my timestamp is in seconds or milliseconds?
A 10-digit number is typically seconds (valid up to year 2286). A 13-digit number is milliseconds. The tool auto-detects which format you have entered.
Is my data sent to a server?
All conversions run in your browser. No data is sent to our servers.
Can I get the current timestamp?
Yes. Click "Now" to insert the current Unix timestamp, useful for generating test values or setting expiry times.

Reviewed and tested May 26, 2026.