Timestamp → date
Date → timestamp
Epoch to date and date to epoch, in seconds or milliseconds, with the unit detected automatically from the number you paste.
Every result shows UTC, your local zone, ISO 8601, and a plain-language relative time, so there is never any ambiguity.
Conversions use your own device clock and time-zone settings. Nothing is uploaded, and it keeps working offline.
What is a Unix timestamp?
A Unix timestamp is the number of seconds since the Unix epoch - midnight UTC on 1 January 1970 - ignoring leap seconds. Because it is a single integer with no time zone attached, it is the most portable way for software to record when something happened. Databases, log files, JSON APIs, JWTs, and version-control systems all lean on it.
The catch is that the same number looks like different clock times depending on where you are. The instant 1700000000 is one wall-clock time in London and another in Tokyo, even though it is the exact same moment. That is the whole point of epoch time - and the reason this converter always shows both UTC and your local zone.
Seconds vs. milliseconds
Traditional Unix time counts seconds (a 10-digit number for today's dates). JavaScript's Date.now() and many web APIs count milliseconds (13 digits). Mixing them up is the most common timestamp bug - a millisecond value read as seconds lands roughly 50,000 years in the future. The Auto setting here picks the unit from the digit count, and you can override it whenever you know better.
Common timestamp reference points
| Moment (UTC) | Unix seconds |
|---|---|
| 1 Jan 1970, 00:00:00 - the epoch | 0 |
| 31 Dec 1969, 00:00:00 | -86400 |
| 13 Feb 2009, 23:31:30 - 1.234 billion | 1234567890 |
| 18 May 2033, 03:33:20 | 2000000000 |
| 19 Jan 2038, 03:14:07 - 32-bit limit | 2147483647 |
One day is 86,400 seconds, one hour is 3,600, and one minute is 60 - useful when adding or subtracting spans by hand.
Frequently asked questions
What is a Unix timestamp?
A Unix timestamp (also called epoch time or POSIX time) is the number of seconds that have elapsed since 00:00:00 UTC on 1 January 1970, not counting leap seconds. It is a simple, time-zone-free way for computers to represent a moment in time as a single number, which is why it appears throughout logs, APIs, and databases.
Is the timestamp in seconds or milliseconds?
Classic Unix time is in seconds and is 10 digits for current dates. JavaScript and many APIs use milliseconds, which is 13 digits. This converter detects the unit automatically from the number's length, and you can also force seconds or milliseconds if you need to.
Why does the date differ from someone else's result?
A timestamp is a single instant, but it displays differently depending on the time zone. The same epoch value is one clock time in UTC and another in your local zone. This tool always shows both UTC and your local time so the difference is clear.
What is the year 2038 problem?
Systems that store Unix time in a signed 32-bit integer can only count up to 03:14:07 UTC on 19 January 2038. One second later the value overflows and wraps to a negative number, misreading the date as 1901. Modern systems use 64-bit timestamps, which push the limit hundreds of billions of years into the future.
Can a Unix timestamp be negative?
Yes. Dates before 1 January 1970 are represented as negative numbers - for example, -86400 is 31 December 1969. This converter accepts negative values and shows the correct pre-1970 date.
Is my data sent anywhere?
No. Every conversion runs in JavaScript in your browser using your device's own clock and time-zone settings. Nothing is uploaded or tracked, and the page keeps working offline once loaded.