Skip to content

Unix Timestamp Converter

Convert a Unix timestamp in seconds or milliseconds to a readable date in UTC, your local time and ISO 8601, or turn a date and time into a timestamp. Shows the current Unix time live.

Timestamp to date
Seconds or milliseconds since January 1, 1970, 00:00:00 UTC. Negative values are moments before 1970.
Automatic: 100,000,000,000 or more (ignoring the sign) is read as milliseconds.

Current Unix time:

Date to timestamp
Time zone

Read the guide What Is a Unix Timestamp and How Do You Read One?

How to use the converter

The tool has two parts.

  • Timestamp to date: paste a timestamp and press Convert. The tool shows the moment in UTC, in your local time zone and in ISO 8601 format, together with the value in both seconds and milliseconds. Now fills in the current timestamp.
  • Date to timestamp: pick a date and a time (seconds are optional), choose whether that time is Local time or UTC, and press Convert. You get the timestamp in seconds and in milliseconds.

The current Unix time is shown above the buttons and updates every second while the page is visible.

What a Unix timestamp is

A Unix timestamp (also called epoch time or POSIX time) counts the seconds that have passed since January 1, 1970, 00:00:00 UTC, a moment known as the Unix epoch. Every day counts as exactly 86,400 seconds; leap seconds are ignored. Because the count is tied to UTC, the same timestamp means the same instant everywhere in the world. Only the way it is displayed changes with the time zone.

Many programming languages, including JavaScript and Java, count milliseconds instead of seconds. A millisecond timestamp has three more digits: 1700000000 seconds and 1700000000000 milliseconds are the same moment.

Seconds or milliseconds?

With Detect automatically, a value of 100,000,000,000 or more (ignoring the sign) is read as milliseconds and anything smaller as seconds. As seconds, that limit lies in the year 5138; as milliseconds it is March 3, 1973. So any realistic present-day timestamp is detected correctly. If you work with very old millisecond values or far-future second values, choose the unit yourself.

Worked examples

  • 1700000000 is Tuesday, November 14, 2023 at 22:13:20 UTC, written in ISO 8601 as 2023-11-14T22:13:20Z.
  • January 1, 2026 at 00:00:00 UTC is 1767225600. From 1970 to 2026 there are 56 years with 14 leap days, so 20,454 days × 86,400 seconds = 1,767,225,600.
  • Negative timestamps count backwards: −86400 is December 31, 1969 at 00:00 UTC, and January 1, 1900 is −2208988800.

The year 2038 problem

Older systems store the timestamp as a signed 32-bit integer, whose largest value is 2,147,483,647. That is reached on January 19, 2038 at 03:14:07 UTC. One second later such a counter overflows and jumps back to December 13, 1901. Modern systems use 64-bit time and are not affected, but old embedded devices, file formats and databases may be. The converter adds a note whenever a timestamp falls outside the 32-bit range.

Good to know

  • The supported range is the year 1 to the year 9999, using the Gregorian calendar throughout.
  • Local time and daylight saving rules come from your browser. If a local time does not exist because clocks jump forward, the tool says so and uses the shifted time.
  • Fractions of a second are accepted and rounded to the nearest millisecond.

Frequently asked questions

Is a Unix timestamp the same in every time zone?

Yes. A timestamp counts seconds since a fixed instant in UTC, so it identifies the same moment everywhere. Only the local clock time shown for it differs between time zones.

How do I tell whether a timestamp is in seconds or milliseconds?

Count the digits. Present-day timestamps have 10 digits in seconds and 13 digits in milliseconds. The converter detects this automatically: values of 100,000,000,000 or more are treated as milliseconds. You can also choose the unit yourself.

What happens in 2038?

A signed 32-bit counter can hold at most 2,147,483,647 seconds, which is January 19, 2038 at 03:14:07 UTC. Systems that still store time that way will overflow at that moment. Systems using 64-bit time can represent dates billions of years away.

Can a Unix timestamp be negative?

Yes. Negative values are moments before January 1, 1970. For example, −86400 is exactly one day earlier, December 31, 1969 at 00:00 UTC.

Does Unix time include leap seconds?

No. Unix time treats every day as exactly 86,400 seconds, so leap seconds are not counted. This keeps date calculations simple, and the difference from atomic time does not matter for everyday use.