How Unix timestamps work
A Unix timestamp — also called epoch time, POSIX time or Unix time — is simply a count of seconds. The count starts at the Unix epoch, which is midnight on 1 January 1970 in Coordinated Universal Time (UTC). Every moment after that is one larger; every moment before is negative. Because it is a single number, a timestamp is unambiguous: it does not depend on the reader's time zone, calendar locale or daylight-saving rules.
To show a timestamp to a person you convert it to a date in a chosen time zone. The raw number stays the same — only its presentation changes. That is why this converter prints both the UTC date and your device's local date for the same value. Some systems store timestamps in milliseconds rather than seconds; the tool detects this from the number of digits and lets you override the unit.
Example timestamps
| Unix timestamp (s) | UTC date | What it marks |
|---|---|---|
| 0 | Thu, 1 Jan 1970 00:00:00 | The Unix epoch itself |
| 1000000000 | Sun, 9 Sep 2001 01:46:40 | One billion seconds |
| 1700000000 | Tue, 14 Nov 2023 22:13:20 | Worked example above |
| 2147483647 | Tue, 19 Jan 2038 03:14:07 | 32-bit signed limit (Y2038) |
Reference note: timestamps ignore leap seconds and are measured from 1 January 1970 UTC. Local times shown by this tool use your browser's time zone and daylight-saving settings.
Frequently asked questions
- What is a Unix timestamp / epoch time?
- It is the number of seconds since 1 January 1970 00:00:00 UTC, not counting leap seconds. A single integer represents a moment in time independently of any time zone, which makes it easy for computers to store and compare dates.
- How do I convert a timestamp to a date?
- Add the timestamp's seconds to the epoch (1 Jan 1970 UTC). Paste the value into the Timestamp → Date box above and the tool shows it in UTC, in your local time, and as a relative time like "2 days ago".
- What's the difference between seconds and milliseconds timestamps?
- A seconds timestamp counts whole seconds (about 10 digits today); a milliseconds timestamp counts thousandths of a second (about 13 digits) and is 1000× larger. JavaScript and many APIs use milliseconds; Unix tools and databases often use seconds. The tool auto-detects by length.
- What time zone is epoch time in?
- The raw timestamp has no time zone — it is always counted from midnight UTC on 1 January 1970. To display it you convert to a zone, which is why the tool shows both the UTC date and your local date.
- What is the year 2038 problem?
- Signed 32-bit timestamps can only reach 2,147,483,647 seconds, which occurs at 03:14:07 UTC on 19 January 2038. After that the value overflows and may become negative. The fix is 64-bit timestamps, used by most modern systems.
- How do I get the current Unix time?
- It is shown live at the top of this page; use the Copy button. In code, use
Math.floor(Date.now()/1000)in JavaScript,time.time()in Python, ordate +%son Linux and macOS.