Free Online Unix Timestamp to ISO 8601 Converter

Convert Unix timestamp to ISO 8601 instantly, in UTC, with milliseconds detected and a table of well-known timestamps.

Converter

Unix, ISO 8601, SQL, Excel, .NET Ticks & 33 Formats Total

Convert any date/time between timestamp formats, or pick one from a calendar - all in UTC

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Results are provided for informational purposes only and may contain errors. Please verify important information independently. Use of this tool is at your own risk.

How to convert Unix timestamp to ISO 8601

Convert Unix timestamp to ISO 8601 instantly. Paste a value and see the result in UTC as you type, with the method and a table of well-known timestamps.

  1. Type or paste your Unix timestamp value, such as 1700000000, into the box above.
  2. The result appears right away: 1700000000 is 2023-11-14T22:13:20.000Z.
  3. Copy the result, or choose from 33 date and time formats in the From and To boxes.

How the conversion works

A Unix timestamp is the number of seconds since 1 January 1970, 00:00:00 UTC. Divide it by 86,400 (the seconds in a day) to get whole days since then; the remainder is the time of day. 13-digit values are milliseconds, as JavaScript's Date.now() returns them, and the converter detects them automatically.

Well-known Unix timestamp values

Unix timestampISO 8601
01970-01-01T00:00:00.000Z
9466848002000-01-01T00:00:00.000Z
10000000002001-09-09T01:46:40.000Z
12345678902009-02-13T23:31:30.000Z
17000000002023-11-14T22:13:20.000Z
17672256002026-01-01T00:00:00.000Z
20000000002033-05-18T03:33:20.000Z
21474836472038-01-19T03:14:07.000Z

Unix timestamp and ISO 8601 explained

A Unix timestamp counts the seconds since 1 January 1970, 00:00:00 UTC (the Unix epoch). Most programming languages, databases and APIs store time this way.

ISO 8601 is the international date and time standard, written like 2026-01-01T00:00:00.000Z. The Z means UTC. It is unambiguous and the format most JSON APIs use.

Frequently asked questions

Is the result in my time zone?

No, every result is in UTC, so it is the same for everyone. To get local time, add your UTC offset, for example +2 hours for Central Europe in summer.

What if my timestamp has 13 digits?

Then it is in milliseconds. The converter reads 13-digit values as milliseconds, 16 digits as microseconds and 19 digits as nanoseconds.

What is the year 2038 problem?

Systems that store Unix time in a signed 32-bit number stop at 2147483647, which is 19 January 2038, 03:14:07 UTC. After that the number overflows. 64-bit systems are not affected.

Is this tool free?

Yes, it's free to use. No signup, no email required. Get results on this page.

How do I get my result?

Use the tool on this page. Your result appears here; no email delivery is required.