Unix Timestamps: epoch time explained
A short guide to Unix time — what timestamps are, seconds vs milliseconds, how timezones fit in, and how to convert both ways.
Open the Timestamp Converter →What this tool does
The Unix Timestamp Converter shows the current epoch time live, converts a timestamp into local, UTC and ISO dates with a relative description, and converts a date back into seconds and milliseconds — all in your browser.
What is a Unix timestamp?
A Unix timestamp counts the seconds since the Unix epoch: midnight UTC on 1 January 1970. Because it's a single number in UTC, it's an unambiguous, timezone-free way to store and compare moments in time — which is why databases and APIs love it.
Seconds vs milliseconds
Classic Unix time is in seconds (10 digits today). JavaScript's
Date.now() and many APIs use milliseconds (13 digits). The
converter auto-detects based on magnitude, or you can force seconds or milliseconds.
Timezones and UTC
The timestamp itself is always UTC. When you convert it, the tool shows both your local time and UTC so you can see the offset. When converting a date to a timestamp, the date-time input is read in your local timezone.
Common uses
- Reading timestamps from logs, databases, and API responses.
- Setting
exp/iatvalues for tokens. - Debugging timezone and off-by-1000 (seconds vs ms) bugs.
It runs locally
Conversions use your browser's date functions — nothing is uploaded.
FAQ
What is a Unix timestamp?
Seconds since 1 Jan 1970 UTC — a timezone-free instant in time.
Seconds or milliseconds?
10 digits is seconds, 13 is milliseconds; the tool auto-detects.
Is my data uploaded?
No — it all runs in your browser.
Ready to try it? Open the Timestamp Converter →