keisoku

UNIX Timestamp to Date Converter

Convert a UNIX timestamp (seconds or milliseconds) into a readable date and time in JST or UTC, with the weekday and ISO 8601 string included.

Input

Input unit

Display time zone

Result

Result (JST)

Wed, 11/15/2023 07:13:20

Japan Standard Time (JST)

Wed, 11/15/2023 07:13:20

Coordinated Universal Time (UTC)

Tue, 11/14/2023 22:13:20

Weekday (JST)

Wed

Japan Standard Time (JST)2023-11-15 07:13:20 (+09:00)
Coordinated Universal Time (UTC)2023-11-14 22:13:20 (+00:00)
ISO 8601 (UTC / Z)2023-11-14T22:13:20.000Z
Epoch seconds1,700,000,000 s
Epoch milliseconds1,700,000,000,000 ms

How it works

  • UNIX time is the number of seconds elapsed since January 1, 1970, 00:00:00 UTC. This tool accepts both seconds (10 digits) and milliseconds (13 digits) as input.
  • Mixing up the seconds and milliseconds units gives a date that is off by a factor of about 1000. As a rule of thumb, typical APIs and logs use roughly 10-digit seconds and 13-digit milliseconds.
  • You can switch the display time zone between Japan Standard Time (JST, UTC+9) and Coordinated Universal Time (UTC). The same UNIX value shows a 9-hour difference between JST and UTC.
  • The result also shows the weekday and the ISO 8601 string (with a trailing Z), so you can use it directly for log investigation and data reconciliation.
  • Pressing the Now button automatically fills the input with the current UNIX time in the selected unit.
  • This tool does not support daylight saving time. JST is always calculated as a fixed offset (UTC+9) throughout the year.