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About

Unix Timestamp Converter

Paste a Unix timestamp and read it as a date in UTC and in your own time zone, or type a date and get its timestamp. Seconds, milliseconds, microseconds and nanoseconds are told apart by their length, and the tool says which it assumed; a column of thousands converts at once and pastes back into a spreadsheet.

What it does

  • Seconds, milliseconds, microseconds and nanoseconds told apart by length, the guess said out loud, and the other readings a click away.
  • Excel serial dates, Windows FILETIME and LDAP times, .NET ticks, Apple, Chrome and NTP times, and Discord and X IDs, both ways.
  • The time inside a version 1, 6 or 7 UUID, a ULID and a MongoDB ObjectId.
  • Dates written as ISO 8601, RFC 2822, HTTP, JavaScript’s Date or 14.11.2023; one with no offset is read in the zone you choose.
  • A clock change named: a time that never happened, or one that happened twice, with the second of the two a click away.
  • Out as ISO 8601, RFC 2822, an HTTP date, SQL, the ISO week and how long ago, each with its own Copy.
  • Up to 10,000 lines at once: copy a column back, a line for each line, or download a CSV.
  • The time now, ticking, in seconds and milliseconds.

How to use it

  1. Paste a timestamp, a date or an ID, or many of them, one a line.
  2. Check what it was read as, and choose the epoch yourself if the guess is wrong.
  3. Pick the time zone for dates written without an offset.
  4. Copy the form you need, or the whole column.

What it does not do

  • Leap seconds: Unix time counts every day as 86,400 seconds, so 23:59:60 reads as the second after it, as POSIX has it.
  • GPS and TAI time: both need a table of leap seconds, which changes whenever one is announced.
  • Dates before 271821 BC or after 275760: JavaScript’s dates end there, and most languages end sooner.
  • A day and month that could be either way round, like 03/04/2024: the tool asks for the year first rather than guess.

Questions

Is my timestamp in seconds or milliseconds?

Count the digits: today one in seconds has 10, in milliseconds 13, in microseconds 16 and in nanoseconds 19. The tool reads the length the same way, says which it chose, and offers other readings when the date is an unlikely one.

Why is an Excel date one day off?

Excel counts 29 February 1900, a day that never happened, because Lotus 1-2-3 did. Every serial from 61 on is a day further along than a plain count; the tool follows Excel, and says so when it meets serial 60.

What is the year 2038 problem?

A signed 32-bit count of seconds runs out at 03:14:07 UTC on 19 January 2038, and the next second wraps round to 1901. Systems that keep time in 64 bits, as most now do, run on for billions of years.

Which time zone does it use?

UTC always, and beside it the zone you choose, which starts as your own. A date typed without an offset is read on that zone’s clock; one with an offset or a Z is read as written.

Everything here runs in your browser. Nothing you type, paste or open is uploaded, and there is no account and no queue. How that works.

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