Unix Timestamp Converter

Convert Unix timestamps (seconds or milliseconds) to dates and back, in your local time zone or UTC.

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How to use

  1. “Now” at the top shows the current Unix time in seconds and in milliseconds, updated every second, each with a copy button.
  2. Under “Unix timestamp → date”, enter a timestamp. Whether it is in seconds or milliseconds is detected from the number of digits and shown next to the input.
  3. Read the result as Local time, UTC, ISO 8601 and Relative (how long ago or from now), and copy any row.
  4. Under “Date → Unix timestamp”, pick a date and time down to the second, and choose Local time or UTC to set which time zone that date is in.
  5. Copy the result in Seconds, Milliseconds or ISO 8601.

Frequently asked questions

Is anything sent to a server?
No. All conversions happen in your browser.
Seconds or milliseconds?
Unix time is usually counted in seconds (10 digits for current dates), while JavaScript and many APIs use milliseconds (13 digits). Numbers with 12 or more digits are treated as milliseconds, shorter ones as seconds. Negative values (dates before 1970) and decimals are accepted.
Which time zone is used?
The Local time row uses your browser’s time zone and the UTC row uses UTC; the ISO 8601 value is always in UTC (it ends in Z). In “Date → Unix timestamp”, the Local time / UTC choice decides which time zone the entered date is read in.
Does this tool have the year 2038 problem?
No. The 2038 problem affects systems that store Unix time as a signed 32-bit number, which overflows after 2147483647 (2038-01-19 03:14:07 UTC). This tool uses JavaScript dates, which reach the year 275760.
Why is the relative time only approximate?
It is rounded to the largest unit that fits, counting a month as 30 days and a year as 365 days, so “in 2 years” is not an exact calendar difference.