Technical time
Unix timestamp converter
Convert a UTC date and time into Unix seconds and milliseconds.
How to use this calculator
Enter UTC date and time. Convert a UTC date and time into Unix seconds and milliseconds. The answer updates when you change an input.
Understanding the result
Unix time counts elapsed seconds from the UTC epoch and does not encode a display timezone.
Common questions
What assumptions does this result use?
The entered date/time is explicitly treated as UTC; leap seconds are not represented by JavaScript Date.
Are intermediate values rounded?
No. The calculation retains JavaScript number precision internally and formats only the displayed result unless the stated method requires a discrete whole value.