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Unix Timestamp Converter

Convert Unix time to dates and back.

Use the Unix Timestamp Converter tool

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What this unix timestamp converter does

Unix time counts the seconds since 1 January 1970 at 00:00 UTC, ignoring leap seconds. This converter turns a timestamp into an ISO 8601 string, a UTC date and your local time, and turns a chosen local date and time back into seconds and milliseconds.

Auto-detect uses magnitude: current timestamps in seconds are around ten digits, while the same moment in milliseconds is thirteen. A value of 100 billion or more is treated as milliseconds, which separates the two ranges for any realistic date.

Why use it

  • Read a timestamp from a log, token or database.
  • Generate an expiry value for an API request.
  • Check whether a value is in seconds or milliseconds.

How to use it

  1. 1Paste a timestamp and choose auto, seconds or milliseconds.
  2. 2Read the ISO, UTC and local representations.
  3. 3For the reverse direction, pick a date and time and copy the seconds value.

Worked examples

Epoch

Input

0 seconds

Output

1970-01-01T00:00:00.000Z

Recent timestamp

Input

1700000000

Output

2023-11-14T22:13:20.000Z

Common mistakes

  • Sending seconds to an API that expects milliseconds, producing a date in 1970.
  • Forgetting that the local representation depends on the browser's time zone.
  • Assuming Unix time accounts for leap seconds; it does not.

Frequently asked questions

How do I tell seconds from milliseconds?
Seconds timestamps for current dates have ten digits; milliseconds have thirteen. The auto option uses this magnitude difference.
What time zone is the displayed date in?
Both are shown: the ISO value is UTC, and the local value uses your browser's time zone.
Do negative timestamps work?
Yes. They represent dates before 1970 and are valid as long as they fall within the JavaScript date range.

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