Convert Unix timestamp to date
Paste one or more Unix timestamps and get each one as a UTC date in ISO 8601. Runs in this tab. Your inputs stay in this browser.
Input
Plain text, one Unix timestamp per line. Blank lines give no row but count toward the line limit, and whitespace around each line is trimmed. Up to 1 MB and 10,000 lines. A line break at the very end does not count as another line.
Output
CSV with a header input,unit,iso_utc. One row per timestamp, in the order given, each row ending in CRLF, the last one too. A magnitude, ignoring the minus sign, at or above 100000000000 is read as milliseconds, otherwise as seconds. Only seconds and milliseconds are read, never microseconds or nanoseconds. The date is UTC in ISO 8601 at seconds precision. Milliseconds are rounded down to the whole second, before 1970 too.
Limits
- Dates are UTC only, with no time zone, locale or offset.
- Digits with an optional leading minus. Years 0001 to 9999. A value in seconds reaches only the year 5138, because a value at or above 100000000000 is read as milliseconds.
- No date to timestamp, no natural language dates.
How this was made
The manifest, the first page and the first eight fixtures came from the synthesis stub. Later fixtures and parts of this page's wording were written by hand and Cleared again. The core transform was written by hand into the stub registry: there is no model in this factory, and the stub refuses any PRD it has no hand written entry for.
Errors
Every error names the field, the rule, and shows a small valid example. A line that is not a timestamp is named by its line number. There is no support desk.
Inputs not stored
This runs in your browser tab. Your inputs are not uploaded or stored. The tool sets no cookie, uses no local storage and sends no analytics about your inputs.