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Unix Timestamp Converter
Convert Unix timestamps in seconds or milliseconds and readable dates to ISO and UTC formats instantly.
Your input is processed only as required by this tool.
Unix Timestamp Converter
Unix timestamps represent an instant as elapsed time from the Unix epoch. Different systems use seconds or milliseconds, which can make debugging dates confusing. This converter detects common numeric timestamp sizes and also accepts date strings supported by the browser.
How to use it
- Paste or type the value you want to process.
- Choose the operation or algorithm when the tool offers options.
- Generate the result locally in your browser, then copy it without uploading the input to Ciatto Tools.
How to read the result
The ISO output uses UTC with the Z suffix, while the UTC string is a human-readable representation of the same instant. Milliseconds and seconds are also returned so you can move between API formats without manual arithmetic.
Limitations
Human-readable date strings without an explicit timezone can be interpreted according to browser rules. For unambiguous conversions, prefer ISO 8601 values that include Z or a numeric timezone offset.
Frequently asked questions
Is a Unix timestamp in seconds or milliseconds?
Both conventions exist. Many Unix tools use seconds while JavaScript commonly uses milliseconds. This converter accepts either common magnitude.
What timezone is a Unix timestamp in?
A Unix timestamp represents an absolute instant and is not itself tied to a local timezone.