Unix Timestamp Converter

1. Choose a direction: timestamp to date, or date to timestamp.
2. Enter a timestamp in seconds, or pick a date.
3. Read the result in UTC.
4. See the ISO 8601 form or the value in milliseconds.

Here is what each result means:

A Unix timestamp is a way of representing a moment in time as a single number: the count of seconds that have passed since the Unix epoch, which is midnight UTC on 1 January 1970. So the timestamp 0 is the epoch itself, and 1700000000 is a moment in November 2023. It is also called epoch time or POSIX time.

Storing time as one number is convenient for computers. It makes it easy to compare two moments, add or subtract durations, and store a time compactly, without worrying about time zones, month lengths or daylight saving. This is why Unix timestamps are used throughout programming, databases and web APIs.

Because the count is in UTC, the same timestamp refers to the same instant everywhere in the world; only the local clock time differs. Some systems store the count in milliseconds rather than seconds, giving a number about a thousand times larger, which this converter detects and handles automatically.

It converts between the seconds count and a calendar date, both in UTC.

1. For a timestamp, the seconds are added to the epoch to get the UTC date and time.
2. Very large values are read as milliseconds rather than seconds.
3. For a date, the timestamp is the seconds from the epoch to midnight UTC of that date.

For calendar tools, see the day of the week calculator and the date calculator.

Convert the timestamp 1700000000.

Result: it is Tue, 14 Nov 2023 22:13:20 GMT, or 2023-11-14T22:13:20Z in ISO 8601. The timestamp 0, by contrast, is the epoch itself: 1 January 1970 at midnight UTC.

Timestamps come in two common resolutions.

A millisecond timestamp is about a thousand times larger than a seconds one for the same moment. This converter assumes seconds by default and treats very large values as milliseconds, so both work.

Each way of writing a time suits a different job.

A timestamp is compact and easy for machines to compare, but hard for people to read. Converting it to a human date or ISO 8601 makes it understandable, which is exactly what this tool does.

Seconds or Milliseconds

The resolution changes the size of the number; the converter detects milliseconds automatically.

UTC vs Local Time

Timestamps are in UTC, so the result is UTC; your local clock may show a different hour.

Time of Day

A date alone has no time, so a date converts at midnight UTC.

Programming

Read a timestamp from a log, database or API in a human form.

Debugging

Check what date a stored timestamp represents.

Scheduling

Turn a date into a timestamp for a script or config.

1. Mixing Seconds and Milliseconds

A millisecond value is a thousand times larger. Feeding it as seconds gives a date far in the future.

2. Forgetting UTC

Timestamps are in UTC, so the result may differ from your local clock by several hours.

3. Expecting a Time from a Date

A date alone has no time of day, so it converts at midnight UTC.

4. Off-by-one at the Epoch

Timestamp 0 is the epoch itself, 1 January 1970, not one second later.

5. Very Old or Far-future Dates

Extreme values can fall outside the range a date can represent.

Conversions are exact in UTC for whole-second timestamps within the supported range.

It is the number of seconds since 1 January 1970 at midnight UTC, called the epoch. The timestamp 1700000000 is a moment in November 2023.

Add the seconds to the epoch, 1 January 1970 UTC. This converter does it instantly: 1700000000 becomes 14 November 2023 at 22:13:20 UTC.

The epoch is the starting point of Unix time: midnight UTC on 1 January 1970. It is the moment when the timestamp equals zero.

A seconds timestamp counts whole seconds; a milliseconds one counts thousandths, so it is about a thousand times larger. JavaScript uses milliseconds by default.

Yes. A Unix timestamp always refers to UTC, so the same number is the same instant worldwide. Your local clock time may differ by your time-zone offset.

It changes every second. Enter the current seconds count to see the date, or pick today's date to get the timestamp at midnight UTC.

A date on its own carries no time of day, so the converter uses 00:00 UTC. To include a time, add the seconds for that time to the result.

Systems that store timestamps in a 32-bit signed number overflow in January 2038. Modern systems use 64-bit values, which avoid the issue for billions of years.

No. The calculation runs in your browser and nothing you enter is stored or sent anywhere, unless you choose Save, which keeps the result only on this device.

• Unix time (Wikipedia).
• ISO 8601 (Wikipedia).
• Year 2038 problem (Wikipedia).