Unix timestamp converter
A signed 32-bit integer holds seconds up to 2,147,483,647, which runs out at 03:14:07 UTC on 19 January 2038. Systems still storing timestamps that way will wrap to 1901. It is the same shape of problem as Y2K and has been known about for decades — 64-bit time handles it, and most modern systems have moved, but embedded devices are still being found.
A Unix timestamp counts seconds since midnight UTC on 1 January 1970. 1767225600 is 1 January 2026. Values with thirteen digits are milliseconds rather than seconds, which this tool detects by magnitude.
How to convert a timestamp
The seconds-versus-milliseconds ambiguity is the most common problem with timestamps in practice. JavaScript works in milliseconds, most Unix tooling and databases in seconds, and a value in the wrong unit lands in 1970 or in the year 57000 rather than failing. Ten-digit values are seconds for any date between 2001 and 2286; thirteen-digit values are milliseconds. That heuristic is what this tool uses and it is right for essentially every real timestamp.
Questions
The number of seconds since midnight UTC on 1 January 1970, ignoring leap seconds.