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Unix Timestamp ConverterFree online date & time calculator — instant results, no sign-up

Convert a date to a Unix timestamp and back.

Inputs

Unix timestamp (seconds)
0
Milliseconds0
UTC dateThu, 01 Jan 1970 00:00:00 GMT

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About the Unix Timestamp Converter

The Unix Timestamp Converter converts a calendar date into seconds and milliseconds since the Unix epoch and supports interpreting Unix timestamps as dates. For the default Date of 2026-10-23, it represents midnight UTC as 1,792,713,600 seconds and 1,792,713,600,000 milliseconds.

Date
The calendar date to convert, entered in YYYY-MM-DD format and interpreted as midnight UTC; the default is 2026-10-23.

Formula and method

S = (D − E) / (1 second); M = 1000 × S; D = E + S × (1 second). For D = 2026-10-23 at midnight UTC, S = 1,792,713,600 and M = 1000 × 1,792,713,600 = 1,792,713,600,000.
  • DThe date and time being converted, with a date-only input treated as midnight UTC.
  • EThe Unix epoch: 1970-01-01 at 00:00:00 UTC.
  • SUnix timestamp in seconds since the epoch, excluding leap seconds.
  • MUnix timestamp in milliseconds since the epoch.

Parse the Date as a calendar date, set its time to 00:00:00 UTC, and calculate the elapsed Unix-time seconds since the epoch. Multiply that result by 1,000 for milliseconds, then format the same instant as a UTC date string. To convert back, interpret the timestamp in the correct unit and add its elapsed duration to the epoch; divide a millisecond timestamp by 1,000 before using the seconds-based formula.

Worked example

These are the calculator's starting values and the results it actually produces for them.

Inputs

  • Date1970-01-01

Results

  • Unix timestamp (seconds)0
  • Milliseconds0
  • UTC dateThu, 01 Jan 1970 00:00:00 GMT

How to use the Unix Timestamp Converter

  1. 1Enter the Date in YYYY-MM-DD format, or keep the default 2026-10-23.
  2. 2Treat the selected date as midnight UTC rather than midnight in your local time zone.
  3. 3Read the Unix timestamp (seconds) result: 1,792,713,600 for the default date.
  4. 4Read the Milliseconds result: 1,792,713,600,000, which represents the same instant in a smaller unit.
  5. 5Check that the UTC date row reads Fri, 23 Oct 2026 00:00:00 GMT.

Reading your result

Unix timestamp (seconds) is the elapsed Unix-time count from the epoch: 1,792,713,600 for the default input. Milliseconds shows that same instant as 1,792,713,600,000; it is not a later date. UTC date provides the human-readable equivalent, Fri, 23 Oct 2026 00:00:00 GMT. The GMT suffix here denotes the zero-offset time used for the UTC display.

Limitations

A date-only input does not specify a time of day or time zone, so this example assumes midnight UTC. Local midnight may produce a different timestamp, and displaying the result in a local time zone may change the calendar date. Unix time does not count leap seconds. The supported date range and treatment of fractional seconds depend on the implementation; a date-only input cannot specify sub-day precision. The listed Date input documents the date-to-timestamp workflow, not the interface for entering a timestamp in the reverse direction.

Common questions

Why does 2026-10-23 produce a time of 00:00:00 GMT?+

The input contains only a date, so the conversion uses midnight UTC. That makes the full displayed instant Fri, 23 Oct 2026 00:00:00 GMT.

Should I use 1,792,713,600 or 1,792,713,600,000 in another system?+

Use 1,792,713,600 when the receiving system expects Unix seconds and 1,792,713,600,000 when it expects milliseconds. Check that system's documentation, since using the wrong unit gives an incorrect date.

How do I convert the default timestamp back to a date?+

Interpret 1,792,713,600 as seconds since the Unix epoch, then format the resulting instant in UTC. For 1,792,713,600,000 milliseconds, first divide by 1,000. Both return Fri, 23 Oct 2026 00:00:00 GMT.

Does daylight saving time change a Unix timestamp?+

No. A Unix timestamp identifies an instant independently of local daylight saving rules. Those rules affect its local clock display, not its UTC value.

Does the calculator save my information?+

Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.

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Results are estimates for informational purposes and are not financial, medical or legal advice.