Dates and time
Unix timestamp converter
Convert Unix seconds or milliseconds to a UTC date, or convert an explicit UTC date/time into a Unix timestamp.
Runs in your browser. Inputs stay on this page and are not uploaded or added to the URL.
Your result
How to use this tool
Choose seconds or milliseconds and a conversion direction. Negative timestamps represent instants before 1970. The tool always displays UTC and requires Z for a date-time input, so it does not accidentally apply your computer’s local time zone.
Second timestamps may have up to three fractional digits; millisecond timestamps must be whole numbers. Supported output years are 0001–9999. This follows JavaScript/POSIX-style epoch time and does not represent leap seconds.
Worked example
0 seconds → 1970-01-01T00:00:00.000Z. −1 second → 1969-12-31T23:59:59.000Z.
References and method
Contifield is an independent utility site. Reference publishers do not endorse this tool.
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