Date to Unix Timestamp
Convert a date/time into a Unix timestamp.
About Date to Unix Timestamp
Date to Unix Timestamp converts a human-readable date and time into Unix time — seconds (and milliseconds) since January 1, 1970 UTC. APIs, databases and logs speak Unix time constantly, and building request payloads or test fixtures means converting the other way from how humans think.
The crucial detail this tool gets right is the time zone: you choose which zone the wall-clock time you entered belongs to, which is exactly where manual conversions (and many quick scripts) go wrong.
How to use
- Pick the wall-clock moment in "Date & time".
- Choose which zone that reading belongs to under "Interpret input as time zone".
- Click "Convert to Unix" to get seconds, milliseconds and the ISO 8601 UTC form.
- "Now (UTC)" fills in the current moment if you just need a fresh timestamp.
Frequently asked questions
Should I use seconds or milliseconds?
Unix convention is seconds; JavaScript and many APIs use milliseconds. A 10-digit value today is seconds, 13 digits is milliseconds — passing one where the other is expected puts you decades off, a classic bug.
Why does the time zone matter if the output is "absolute"?
Because "2026-07-11 09:00" is a different instant in Tokyo than in London. The zone tells the converter which instant your wall-clock reading means; the resulting timestamp is then universal.
What is the year-2038 problem?
Systems storing Unix seconds in signed 32-bit integers overflow on January 19, 2038. Testing with timestamps beyond that date is a legitimate boundary test for long-lived systems.