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Unix Timestamp Converter

Unix time is the standard way computers track time internally, but it is not human-readable on its own. This converter translates a Unix timestamp into a readable date and time, and can also go the other direction — converting any date you choose into its Unix timestamp — supporting both seconds and millisecond precision.

Enter seconds or milliseconds — the unit is detected automatically.

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Your data stays in your browser — this tool runs entirely on the client side and nothing is uploaded to a server.

How to Use the Unix Timestamp Converter

  1. To convert a timestamp to a date, paste the Unix timestamp (in seconds or milliseconds) into the input.
  2. To convert a date to a timestamp, pick a date and time using the date picker.
  3. Results update instantly, shown in both your local timezone and UTC.

What is Unix time?

Unix time (also called epoch time or POSIX time) counts the number of seconds that have elapsed since 00:00:00 UTC on January 1, 1970 — known as the Unix epoch. It is a single, unambiguous, timezone-independent number, which is exactly why it is so widely used internally by computer systems and databases to represent a moment in time.

Seconds vs. milliseconds

Unix timestamps are traditionally expressed in seconds, but many programming languages and APIs (including JavaScript's Date.now()) use milliseconds instead, which is 1,000 times larger. A timestamp of 10 digits is typically seconds; 13 digits is typically milliseconds. Mixing the two up is a very common source of "wrong date" bugs.

Timezone considerations

A Unix timestamp itself has no timezone — it is a single global number. Timezone only enters the picture when converting that number into a human-readable date, since the same instant in time displays as a different local date/time depending on where you are. Always be explicit about whether you're displaying a UTC or local-time representation.

Example

Convert 1700000000 (seconds)
1700000000
2023-11-14T22:13:20Z (UTC)

Tips

  • A 10-digit timestamp is almost always seconds; a 13-digit timestamp is almost always milliseconds.
  • Store timestamps in UTC and convert to local time only for display.

Frequently Asked Questions

What happens after the year 2038?

Systems that store Unix time as a signed 32-bit integer will overflow on January 19, 2038 — this is known as the "Year 2038 problem." Most modern systems use 64-bit integers and are unaffected.

Does Unix time account for leap seconds?

No, standard Unix time ignores leap seconds, treating every day as exactly 86,400 seconds.

Is a Unix timestamp tied to a timezone?

No, it represents a single global instant. Timezone only matters when displaying it as a human-readable date.

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