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Unix Timestamp Converter

Convert a Unix timestamp into a readable date. Seconds and milliseconds look identical apart from their magnitude, so the tool detects which you pasted and tells you — reading one as the other puts you in 1970 or thousands of years out.

Leave blank to use the current time

UTC

Thu, 01 Jan 1970 00:00:00 GMT

just now · read as seconds

ISO 8601
1970-01-01T00:00:00.000Z
Day
Thursday
Seconds
0
Milliseconds
0

In your timezone (UTC)

Thursday, January 1, 1970 at 12:00:00 AM UTC

Seconds or milliseconds?

Unix time is defined in seconds, but JavaScript, Java and many APIs use milliseconds. The two look alike and differ by a factor of a thousand, so reading one as the other lands you in 1970 or far in the future. This tool detects which you pasted and says so — override it above if the guess is wrong.

How to use this tool

  1. Paste a timestamp, or leave the field empty to see the current time.
  2. The unit is detected automatically; override it if the guess is wrong.
  3. The date is shown in UTC and in your own timezone.

Notes and limitations

  • Unix time counts seconds since 1 January 1970 UTC. JavaScript, Java and many APIs use milliseconds instead, which is a thousand times larger for the same moment.
  • Detection uses magnitude: a present-day timestamp is around 1.8 billion in seconds and 1.8 trillion in milliseconds, so the two are easy to tell apart.
  • Unix time ignores leap seconds. A day is always exactly 86,400 seconds, which keeps arithmetic simple. Unix time stays aligned with UTC, but the true number of elapsed seconds since 1970 is 27 more than the timestamp shows.
  • A signed 32-bit timestamp overflows on 19 January 2038 — the Year 2038 problem. Systems still storing time in a 32-bit integer will wrap to 1901 at that point.
  • The local time shown comes from your device's timezone setting. UTC is the same for everyone and is the safer value to record.
  • Everything runs in your browser and nothing is uploaded. That said, treat any third-party website with caution when handling production data — if a value would cause real damage if leaked, process it with your own local tooling instead.

Frequently asked questions

What is a Unix timestamp?

The number of seconds that have elapsed since midnight UTC on 1 January 1970. Because it is a single number with no timezone attached, it is unambiguous everywhere — which is why it is used for storing times.

Is my timestamp in seconds or milliseconds?

A ten-digit number is seconds; a thirteen-digit one is milliseconds. The tool detects this from the magnitude and shows which it used.

What is the Year 2038 problem?

A signed 32-bit integer can hold Unix time only until 03:14:07 UTC on 19 January 2038. After that it overflows to a negative number, which reads as 1901. Systems using 64-bit time are unaffected.

Why does Unix time ignore leap seconds?

Because treating every day as exactly 86,400 seconds keeps date arithmetic simple and reversible. The trade-off is that the timestamp does not count leap seconds, so it is 27 seconds short of the true elapsed time since 1970, while still matching UTC.

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