Convert a Unix timestamp into a readable date and back - locally in your browser, with no upload.
Running locally on your device ...
Running locally on your device ...
0%
Your files never left your device
No. Everything runs in your browser - your file never leaves your device. How this is verifiable
A Unix timestamp counts the seconds since 1 January 1970 (UTC) and is the standard way computers store time - in log files, databases, APIs and cookies. For humans, though, such a long number is not readable. This tool translates both ways: you enter a timestamp and get the date in ISO 8601 notation (UTC), or you enter a date and get the matching timestamp.
The tool detects automatically what you enter. A plain number is read as a timestamp - distinguishing seconds from milliseconds (thirteen digits and up count as milliseconds). Anything else is parsed as a date. The output always shows both: the date in ISO 8601 (UTC) as well as the timestamp in seconds and in milliseconds, so you can take the value you need directly.
The whole conversion runs entirely locally in your browser in pure JavaScript - your input is not uploaded, not stored, and no foreign library is loaded from a CDN. The calculation is in UTC so the result is unambiguous and reproducible and does not depend on your device time zone.
The best-known online timestamp converter (unixtimestamp.com and similar) works reliably, but needs an internet connection and reloads the page from the server on every visit. This tool even works offline after the first load, with no account and no ads.
| Input formats | Text input |
|---|---|
| Output format | TXT |
| Batch processing | No |
| Processing | Locally in your browser (JavaScript) |
| File upload | None |
Limitations: The calculation is in UTC (world time), not your local time zone - that keeps the result unambiguous. Plain numbers of thirteen digits or more are treated as milliseconds, shorter ones as seconds. If the input is neither a valid timestamp nor a recognizable date, the tool says so honestly instead of guessing.
No. The conversion runs entirely locally in your browser; your input never leaves your device and is not stored.
The number of seconds since 1 January 1970 at midnight UTC. Computers store time this way internally because it is easy to compare and calculate.
Both are detected: a number with thirteen or more digits counts as milliseconds, a shorter one as seconds. The output always shows both values.
So the result is unambiguous and reproducible and does not depend on your device time zone. A timestamp always refers to UTC.
Yes, in any current mobile browser just like on desktop - the input stays local.
No. No account, and after the first load, conversion even works offline.
Yes. The input is not sent to a server, not even for internal or confidential timestamps from log files.