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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 1.7 billion in seconds and 1.7 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 at the cost of drifting from astronomical time by a few seconds since 1970.
  • 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 Unix time is a few seconds away from true astronomical time.

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