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Unix Timestamp to Date

Decode epoch seconds or milliseconds into a readable date and time.

Timestamp → date & time

10 digits = seconds · 13 digits = milliseconds (auto-detect explains which it used).

How it works

  1. A timestamp marks one exact instant; the unit (seconds or milliseconds) tells how finely it counts since 1970-01-01T00:00:00Z.
  2. Auto-detect labels its choice: values under 100,000,000,000 are read as seconds, larger values as milliseconds, and the note under the result tells you which was applied.
  3. The decoded instant is rendered in UTC and in your browser’s local zone, so an instant near midnight is never mistaken for “the wrong day”.

Good to know

  • Negative values decode normally; -1 is one second before the epoch (1969-12-31 23:59:59 UTC).
  • Range limit: ±8,640,000,000,000,000 ms (the JavaScript Date limits, about years −271,821 to 275,760). Values outside are rejected, not wrapped.
  • Fractional seconds are rounded to the nearest millisecond, and the note says so.
Timestamp ToolsFeatured

Unix Timestamp Converter

Convert Unix timestamps to dates and dates to timestamps in seconds or milliseconds.

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Timestamp Tools

Milliseconds to Date

Convert 13-digit epoch milliseconds into readable dates.

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Timestamp Tools

UTC Timestamp Converter

Decode a timestamp into UTC plus major world time zones at once.

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Timestamp Tools

ISO 8601 Date Converter

Parse ISO 8601 strings and build them from a date, time and zone.

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Frequently asked questions

How do I know if my timestamp is seconds or milliseconds?
Count the digits: 10 digits (e.g. 1700000000) is seconds; 13 digits (1700000000000) is milliseconds. Auto-detect states which unit it applied, without silent guessing.
Why does the UTC date differ from the local date?
A timestamp is one instant; local calendars slice it differently. An instant near midnight UTC can be “yesterday” in New York and “tomorrow” in Tokyo. Both views are shown together.
Are negative timestamps supported?
Yes, pre-1970 instants are negative and decode normally; for example, −1 is one second before the epoch (1969-12-31 23:59:59 UTC).